Excavations of 1932-1935

Joined: August 22nd, 2006, 9:29 pm

March 5th, 2010, 2:11 pm #1

After the brief 1931 excavation season, Professor Birley and associates began larger scale excavation in earnest within the fort-proper. Most of this work is still visible today, the biggest bit being the multi-period principia (HQ) in the center of the fort. He summarized the work in his third report to the Society of Antiquaries of Newcastle-upon-Tyne, published in Archaeologia Aeliana, Series IV, Volume XIII (1936), pp. 218-258. It is presented below (minus the long discussion on samian pottery, which will appear separately). As with the reports from 1931 and 1932, please note that these documents are still held under copyright, are owned by the Society of Antiquaries, used here by permission, and not intended to be reproduced or republished. Enjoy the read!

Also, a brief word on dating of the periods. Since Prof. Birley's dig, much has been learned about the chronology of the fort. To make better sense of his findings, keep the following in mind:

* His "3rd C" fort is now known to be the Antonine fort (Periods VI & VI-A, mid-to-late 2nd C).
* His "4th C" or "Constantian" fort is the visible fort, begun ~AD 213, modified around AD 300 (Pds VII - VIII).
* His "Theodosian" or post-AD 369 fort is basically still believed to be the same today (Period IX).


By Eric Birley, I. A. Richmond, and J. A. Stanfield.

[Read on 30th October, 1935.]
The following abbreviations are employed:

AA1-4 = Archaeologia Aeliana, 1st-4th series.
C. = Corpus Inscriptionum Latinarum, vol. VII.
CW2 = Cumberland and Westmorland Transactions, new series.
JRS = Journal of Roman Studies.
The excavations at Chesterholm which began in 1930 have been continued, with brief interruptions during the winter months, for six seasons, but no report has yet been made to this society on the work done there since the summer of 1931.1 In May 1932 I began the examination of the headquarters building (principia) of the Constantian fort -- an examination which was perhaps all the more instructive because it could be made at leisure; for the most part only two men were employed, and it took more than two years to enucleate the structural history of the building and of the earlier principia that was found to underlie it. During the latter part of that period I had the good fortune to secure Mr. Richmond's co-operation; the tracing of the earlier building was almost entirely done by him, and the extent to which I have benefited by his advice in the interpretation of the later material as well is very considerable. The second section of this report, which deals with the structural remains here and on other parts of the site, is mainly due to him, though we are jointly responsible for it; and it is only an alphabetical accident that causes his name to follow mine at its head. It is not yet possible to present a final account of the successive principia; the by-products of their excavation -- pottery, wood, bones, and above all rich architectural remains of the earlier building -- still require further study before the full tale can be told; but it seems desirable to place on record, without further delay, a summary description of the two buildings, together with an account of some ancillary researches on other parts of the site: a section taken through the north rampart of the Constantian fort, with the complex of earlier structures to whose discovery it led, and the successful search for the lateral gateways of the earlier fort. It must be premised that the earlier principia, and therefore the earlier fort as well, faced southward, on an alinement slightly more westerly than that of its Constantian successor; and, as the excavations of 1930 showed, while the side walls of the two forts mainly coincided, the north and south walls of the Constantian fort were some feet inside those of its predecessor. The object, then, of the section through the north rampart was to discover the position of the earlier north wall, east of the north gate, as well as to examine the structure of the Constantian rampart-mound and such stratification as might be found in association with it; the search for the lateral gateways of the earlier fort was guided by the position and alinement of the (south) front of the contemporary Principia, and in this case too there was an opportunity to examine the Constantian rampart-mound. These two pieces of work were done in 1934 and 1935, mainly at the expense of the Durham University Excavation Committee, and afforded useful instruction in archeology for students from both divisions of the University of Durham.

It is a pleasant task to place on record my obligations to others, mainly members of this society, besides Mr. Richmond, who have helped to obtain the results here recorded. A great deal of the spade-work has been done by Mr. Thomas Hepple, whose experience and skill have been invaluable. In the early stages of the work on the principia I had the benefit of Mr. Quintin Waddington's help, and the surveying of the two buildings was carried out by Messrs. M. Hayton and I. Hamilton, on whose work figs. 1-3 are based. The work elsewhere on the site was supervised in part by Messrs. P. H. Blair and R. P. Wright, whose assistance was of very great value, and the complicated survey of the structures below the north rampart was undertaken by Mr. V. R. Abbott, whose admirable plan speaks for itself. The identification of the coins has been undertaken by Mr. Percy Hedley, whose account of them is reserved for the next report; in the present paper we have been able to incorporate his notes on a few coins of particular value for purposes of dating. Exigencies of space as well as time prevent full publication of the incidental finds of pottery and small objects, but it has seemed essential to include in this report a series of figured samian ware, mainly from the early deposit that underlies the structures below the north rampart; in the description of that material, I have been fortunate to secure the co-operation of Mr. J. A. Stanfield, whose intimate knowledge of the material in the most important British collections is reinforced by the artistic skill to which his beautiful drawings testify. The description of pottery other than figured samian ware, which was to have formed the fourth section of this report, comprises selected pieces from the same early deposit and from the early ditches to the west of the present fort, that were examined in 1930 and 1931; the material is of considerable value for the study of the period between Agricola's governorship and the latter part of Trajan's principate, but it will have to be held over until the next report; it is not the least of my privileges to record the help I have, in preparing that material for publication, as well as in the excavation and elucidation of the fort, from my wife.

By Eric Birley and I. A. Richmond.
§1. The Constantian principia. (Fig. 1.)

The headquarters building, or principia,2 which is now so interesting a feature of Chesterholm fort, is the shell of an early fourth-century building, reconstructed and modified after the disaster of A. D. 367. Its original plan did not differ, in its main lines, from the normal arrangements of such buildings in British forts, but there are minor variations. Thus, the front, on the via principalis, has an open-ended verandah stretching from each side of the main entrance, as at Ribchester, Caersws and Mumrills;3 the courtyard has neither ambulatory nor colonnade: but is surrounded by rooms, presumably armamentaria; a large sacellum, centrally placed in the usual series of five rooms opening off the cross-hall, projects some ten feet behind them, while the western room of the five possesses a heated annexe, projecting a like distance. These features occur at other sites, though at no single site in conjunction, and they cause Chesterholm to differ in this as in many other respects from the stereotyped pattern of fort in use upon the adjacent Wall of Hadrian.
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Figure 1
Details may now be added. The rooms bounding the courtyard were approached either from the main entrance passage or from the cross-hall; the courtyard was thus merely a light-well and a passage to the cross-hall, and was not, perhaps, intended to be much used. The nature of its original flooring is uncertain; if flags were used, they were later removed. A drain led rain-water away from its south-west corner, below the floor of' the flanking room and the side entrance to the hall; one of the side-stones used in this drain was the inscription dated to A.D. 213,4 which had split while being cut up for use as a postsocket, and so came to be used where it was out of sight. The cross-hall was entered from the courtyard by a large central doorway, designed for a high wall, as at South Shields;5 there were side-doors at the north ends of its end walls. The west end of the hall was mainly occupied by a long, low platform, approached by a flight of steps, the lowest two of which remain in place, at its south end, and therefore to be recognized as a tribunal. This gives the clue to the interpretation of a number of less well-preserved ruins found in similar positions, often in the past taken for the walls of small rooms, but evidently now to be interpreted as the supporting walls of timber or earthfilled platforms. The feature is borrowed from the tribunalia in legionary headquarters, such as those at Vetera or Lambaesis, which in turn were inspired by the basilicae of Roman towns.

The end rooms of the range of five were approached from the hall by doorways 3 feet wide, but the three central rooms were treated more elaborately, with wide entrances that were originally arched over, built of exceptionally massive and well-dressed masonry; stone-robbers have removed, apparently in the eightecnth century, most of this fine masonry, working in from the west side of the building, where they even removed some of the foundations; but the most easterly block is left in position, to a height of 4 feet, and serves to show the character of what has been removed. The entrance, in these cases, was reduced to a reasonable width by the insertion of a pair of elaborate stone screens, two of which were ultimately used as paving-stones in the courtyard. Slots were cut for the screens in the thresholds and in the piers of the arches. The space left between the slots, about 3 feet, shows considerable wear, except in the entrance to the sacellum, where a strip 9 inches wide shows no sign of wear; there, between the screens, a doorway and threshold of wood or metal, traces of whose insertion remain at the ends of the slots, must have been inserted. The tops of the two screens that were subsequently used as flags also held metal or wooden grilles, for which dowel-holes remain; between the dowel-holes, the issue of pay or the depositing of savings with the signifer, whose concern was with such things,6 has worn deep hollows in the stone. The front of each screen is ornamented by a rectangular panel, containing a lozenge pattern in cable-mould, as at the Corstopitum fountain;7 it may be noted that similar screens have been found at Risingham,8 while grooves to receive them have been observed at Housesteads, as well as in the earlier principia at Chesterholm, and elsewhere. The two end rooms had a more private function, as is shown by their unpretentious doorways; that at the west end had a little, heated inner room at its back, projecting behind the building as far as the sacellum, that offered extra accommodation for the regimental clerks, as at Segontium9 and other sites: it is interesting to find an instance where it forms part of the original design, and not the addition that such a room usually seems to be.

The sacellum has an ante-chapel, with a raised ledge, perhaps for altars, on either side of the flagged passage that led to a flight of steps, the first of which remains, while from its position and size at least two more may be inferred, giving access to the raised floor of the main chapel. This has no sunken strong-room of the elaborate type represented at Chesters or South Shields, but a narrow pit, in shape like an E without the central bar, leaving a solid platform in the centre of the room for altars or an imperial statue, such as that of an emperor in the guise of Hercules which seems to have stood in the headquarters at Bainbridge;10 the pit, which was presumably covered by a wooden frame, was no doubt used to hold valuables, such as the soldiers' savings whose custody was one of the duties of the standard-bearers; it is structurally independent of the sacellum, and was in use after the Theodosian reconstruction, for a complete Crambeck wallsided mortarium was found in it, but it may well be part of the original design.

1 For the excavations of 1930 and 1931, cf. AA4 viii 182-212, ix 216-221; the inscription of A.D. 213 found in the headquarters building in 1933 is given in AA4 xi 127-37, and a fuller reading of the text, by professor Collingwood, in JRS xxiv 218.
2 Cf. AA4 viii 193; CW2 xxx 201.
3 Haverfield, Roman Britain in 1914, p. 12; Proc. Soc. Ant. Scot., lxiii, 423.
4 Cf. AA4 xi 127-37
5 Cf. AA4 xi 87-8.
6 Vegetius, iii 20, and cf. ii 19.
7 AA3 iv 278 and fig. 13.
8 Cf. p. 193 above.
9 Wheeler, Segontium, Cymmrodorion Society 1924, pp. 48-53.
10 That this was Maximianus Herculius seems the simplest explanation of the statue recorded by Camden (Gough's second edition, 1806, iii, 256); it stood on a Severan inscription, on which the name of Alfenus Senecio may be recognized, presumably re-used as a flagstone in the Constantian reconstruction of that fort.

Last edited by SacoHarry on March 5th, 2010, 2:37 pm, edited 4 times in total.

Joined: August 22nd, 2006, 9:29 pm

March 5th, 2010, 2:14 pm #2

§2. The Theodosian reconstruction. (Fig. 2.)

The alterations attributable to A.D. 369 were drastic, and reflect a considerable change in the character of the building, though its function as the administrative centre of the fort is not obscured. The verandah was closed and converted into two store-rooms, with ventilated floors, but without buttresses. In the courtyard, space was gained by obliterating all but the eastern extremity of the room to the east of the entrance passage, and throwing its western portion into the yard; the latter was now paved, in part with roughly dressed flags, in part with re-used stones such as the two screens described above, and a well was dug, 20 feet deep, to the underlying rock; the material found in it was of considerable interest, including an exceptionally fine series of wood. All but one of the rooms flanking the courtyard were now converted into storerooms, with flagged floors resting on low sleeper-walls; the absence of buttresses suggests that they were not intended to hold corn so much as some kind of article that needed to be kept dry, such as spare clothing or equipment: that is to say, they are to be classed as armamentaria still, rather than horrea.
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Figure 2
The level of the cross-hall was raised slightly, receiving a floor of rammed earth in place of cement; and the insertion of two massive bases on its centre line shows that its roof was now supported by less massive main timbers than had been used previously. The tribunal at its west end was now extended 2 feet further north, and received a new front, once faced with orthostats set in moulded slots (one of which is a re-used window-head) that still remain. The five administrative rooms were more drastically changed. In the ante-chapel, there grew up during this period a habit of lighting a fire, which eventually calcined its floor. The side rooms were converted into living-quarters which, like the rooms round the court yard, yielded abundant pottery of the types characteristic of the last period of the occupation of Hadrian's Wall, in particular Huntcliff ware and a large group of painted Crambeck bowls and mortaria; the doorways, wide or narrow, that had led into the hall were walled up, and access to the rooms was now provided only from the sacellum. The eastern pair of rooms was now closely connected, a doorway being broken through the north end of the dividing wall, and a flue inserted in that wall a few feet further south, so that the fumes from an open hearth on the new flagged floor in the western room could heat a hypocaust, with pillars formed of cast-off roofing slates, inserted in its eastern neighbour; a long, narrow compartment was added behind them, with a flagged floor sloping down to the east end of it, where was a sump or lavatory with a drain leading away from it. As has been noted elsewhere,11 this suite resembles the quarters provided, apparently for N.C.O.'s, in barrack-buildings at Birdoswald and South Shields; and it may be added that the corresponding pair of rooms at Housesteads were somewhat similarly arranged in the last period: it looks as if an important minor official, perhaps the signifer, lived permanently at headquarters during the closing years of the occupation. The heated annexe to the western room was now obliterated, but a hypocaust was inserted in that room, the southern part of which was walled off to form a stokehole and wood-store, with access from the via quintana; at this side, however, there was no lavatory attached, and it seems possible that the two western rooms continued to serve as a record-office or tabularium.

§3. Evidence for date.

The evidence for the date of this principiu's construction and the subsequent major alterations is clear. The pottery from the latest occupation is uniformly of types attributable to the period after the "Picts' War," and though the coins from the same level were almost all survivals from the third century or the first half of the fourth, they included a fourth brass of Valentinian II,12 datable to A.D. 388-92; a terminus post quem for the storage arrangement in the room on the west side of the courtyard is provided by a third brass of Constantine II. The former coin is of exceptional interest, as one of the few which directly attest occupation of the Wall district after the usurpation of Magnus Maximus in 383. It seems that the final disaster must have come some years later, though it is not clear whether it was a nucleus garrison, left behind by Maxinius, which was overwhelmed after his fall (as Kipling suggested), or whether the end belongs to a later and obscurer period.

The direct evidence for the construction of the building is slighter, but sufficient. The mortar of its walls, where it has been preserved, shows the same shale-content as had been noticed in the fort wall at the east and north gates, and at the north-west angle;13 there was little pottery, and no such distinctive types as were found among mason's chippings contemporary with the east gate of the fort,14 but the earlier of the two periods here, as at the north gate, must logically be assigned to the Wall period that preceded the Theodosian reconstruction, namely that inaugurated by Constantius Chlorus,15 as is suggested indeed by the re-use in it of a previously re-used inscription of A.D. 213.

§4. The earlier principia. (Fig. 3.)

The fact that the fourth-century building was not the earliest on the site was revealed at an early stage by the occurrence of various subsidences in its walls, suggesting that they were breaking their backs over earlier foundations on different lines. In places, too, fragments of earlier walls protruded, notably in the entrance passage and in the room on its east side, where a moulded threshold underlay the floor over which the flags of the extension of the courtyard had been laid. Starting from this point, exploration further to the east disclosed, still in position, two sills with slots for screens of the type noted above. To the west, the corresponding sills were missing, but, further west still, the terminal room of a southward-fronting range of five was found, with walling intact; and with this as a guide, fragmentary remains of the corresponding end room on the east side were quickly found. The earlier principia, therefore, to which these distinctive five rooms had belonged, faced south instead of north, on a slightly different alinement to that of the later buildings; and it only remained to discover its limits and anatomy.

The west wall of its cross-hall was speedily traced, being marked by an easily recognizable subsidence in the flagged floor inserted in the room on the west side of the courtyard in the later building; it had a side door at the south end, to which corresponded a row of bases for square piers. One base remained in position, while foundations for two others were found; further east, a search for more would have involved too much interference with the later structure to be worth undertaking. There had also been a second row of bases, 6 feet further forward, a little like the double row of piers at Chesters, except that these were of much smaller dimensions, and there was no sign that they had ever held moulded bases. It is more likely that they formed the stone framing of a cement wall, as described below, in the style peculiar to this building. No trace of a colonnaded courtyard was to be found; a cross wall occurs just within that of the later building, and if this was the south front of the building, the courtyard must have been exceptionally wide in comparison with its depth from front to hack; but it may be the north wall of a front ambulatory. Considerable further search did not succeed in establishing the correctness of either alternative.
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Figure 3
Two points about the building are of great interest. It had been unusually elaborate in style. In the sacellum, the sill for the screens was enriched with a deeply cut moulding, while the top was pierced with three dowel holes for an elaborate upper screen; from behind it there had run a bench, of which one course of stones remained, evidently flanking one side of the chapel. The pier to the east had also been a heavy one in stone, of which part of the foundations remained, while the rest can be inferred from the position of the sills in the adjoining room. These sills were a pair, so arranged that each made up half of a well-worn central threshold; and in the room behind them was found the bronze lid of a document-box (capsa), such as the regimental archives were no doubt contained in. On the floor of its cross-hall, below the later courtyard, and among the material that was used to make up the level for the later cross-hall, occurred fragments of rich Ionic column-bases, with fragments of composite capitals, and a relief embodying the Sun God in his chariot, together with small statues once attached to a background, as if from panels or pediments. These fragments will be published later, when the study of them has progressed further. Meanwhile, their enumeration is sufficient to show that the building was one of unusual splendour; allured by the soft sandstone in which they worked, its builders had given free rein to their decorative instincts.

The second notable point is the unusual construction of the building. The soft sandstone, employed for the decoration and the smaller stonework, is not fitted to bear great weight. So, in the higher portions of the building, namely the cross-hall and the range of five rooms opening off it, the builders employed an old Roman device, described by Vitruvius and Tacitus,16 of which examples are familiar to students of Roman Spain or Africa, the homes of the adobe tradition. The softer material, by this device, is cut up into panels and divided by piers of hard stone. Further, not trusting the softer material even then to carry the required weight, the builders laid only a few courses of ashlar, and set upon the sill, so formed, panels of the soft sandstone ground to powder and mixed with tile and lime, so as to form a hard lime concrete. Masses of this material bestrewed the area of the cross-hall of this building; and though the original demolition and subsequent damp had reduced most of it to formless lumps, it was possible to extract some shaped fragments, which showed that it had been moulded in rectangular blocks. The treatment is unique in the Wall area, and without parallel in Britain. As the very different and normal construction of the later buildings at Chesterholm shows, the method is not to be regarded as imposed by peculiar local conditions: it is rather the deliberate choice of an architect determined to exploit the local stone to the full, to achieve decorative effects. In the military area, this phenomenon is as interesting as it is unexpected.

The general date of this building is not in doubt. It was destroyed in the disaster which preceded the Constantian remodelling of the site, and had obviously existed for a considerable time before that, as the worn state of its hard stone thresholds shows. No evidence was found for structural alterations to it, and it may logically be assigned to the period preceding the Constantian, initiated by Severus's governor Alfenus Senecio;17 but it is less certain that the building was erected as early as the time of Severus. An inscription of the time of Severus Alexander, set up in the governorship of Claudius Xenophon, circa A.D. 222, records the restoration of a gate and its towers from the foundation18 -- by a process of elimination, this must have been the porta praetoria, in the south front, which might be expected to invite particularly elaborate treatment and it is possible that the construction of this ambitious headquarters-building may have been part of the same scheme. But the site was certainly re-occupied sooner, as the dedication to Caracalla in 21319 demonstrates. It remains to be seen whether Alfenus Senecio or Claudius Xenephon, both men with African connections, deserves20 credit for the work.

11 AA4 xi 96.
12 The coin will be described in full by Mr. Percy Hedley in the next report; his identification and dating of it are confirmed by Mr. Pearce, to whom he submitted it.
13 Cf. AA4 viii 198-9, ix 217.
14 AA4 viii 199, fig. 3, 1 and 2.
15 AA4 vii 168-9.
16 See Vitr. ii, 8, 17; Tac. Ann. xv, 43. The method is a substitute for timber-framing, as at Urspring principia, O.R.L. xxiv, Taf. ii, iii, v, 2 and p. 13.
17 Cf. AA4 vii 167-9.
18 C. 715; cf. AA4 viii 191.
19 AA4 xi 127-37.
20 L. Alfenus M.f.Qui. Senecio, presumably the father of the Severan governor, who was at one time procurator of Mauretania Caesariensis, was a native of Cuicul in Numidia (Dessau, ILS 9489; Prosopographia Imperii Romani, second edition, i, p. 88, A 520); T. Claudius T.f.Pa.p. Xenophon, under Severus procurator ad bona cogenda in Africa, was probably the father of the governor under Severus Alexander, whose name is patently misspelt on the Chesterholm inscription (Dessau, TLS 1421).

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March 5th, 2010, 2:16 pm #3

§5. The third-century portae principales. (Pl. xix.)

The discovery that the third-century principia faced south, with its back towards the via principalis of the later fort, has as its corollary the conclusion that the third century via principalis lay somewhere near the via quintana of later days. The gates of this street might thus be expected to lie buried below the later rampart, if they were not embodied in it. Accordingly, search was made behind the existing west rampart at a point in line with the southernmost known wall of the early priitcipia. It was very soon evident that we had found an earlier gate. The Constantian rampart-backing was found to cover massive ashlar foundations, set as headers and stretchers upon a firm flagged footing. These projected 6 feet behind the rear face of the later wall. To north of them was a mass of broken rubble, of the soft stone used in the principia, here employed as road-material: to south there still remained a fragment of earlier rampart, composed of clean material, easily distinguishable from the mixed earth of the later mound, and retained by a curving line of upright flat stones, which ended against the masonry. It was evident that the masonry itself formed the south Jamb of a massive, portal, which terminated, as an examination of the front of the Constantian wall soon showed, flush with the later wall-face. Here the large ashlar had been removed, but the footings still existed, while one course and the footing of the fort-wall to south were found abutting upon them. There followed a ten-foot gap, beyond which the footings of the gateway-jamb appeared again, with the fort-wall to north, showing that this was not a spina, but the north jamb of a single portal. It is evident, therefore, that the gate was of simple type, with single entrance, like the portae quintanae of several Hadrianic forts on the Wall: and the massive character of the foundations shows that they were intended to carry a tower.
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Figure 4
Other discoveries made at this point concern the later wall. In the portal of the earlier gate, the later wall had been ill founded, and had sagged outwards. Further northwards, there was a larger bulge still, partly caused by erecting, on the small masonry of the late wall, a massive reconstruction in Theodosian style. Some attempt had been made to correct this by building against the wall a large buttress, of which part of the south wall remained, together with clay and cobble packing within it to north. The west and north faces had, however, been robbed, and it is uncertain how large this structure had been. It is reminiscent of the buttress set against the north face of the west tower at the north gateway.21

From the newly discovered west gate, it is natural to turn to the east gate, excavated by Hedley22 and examined afresh in 1930 and 1934. In its last days, this gateway had been a small postern, from which a flight of steps led down towards the Chainley Burn: and Hedley himself was only in time to prevent further damage after the steps had been removed. The stone-robbers had also removed the north jamb, but the approximate position of this is shown by the existing remains of the curved rampart-revetment which was abutted against it by later builders, as on the south side. It may be assumed that these were the reconstructors of A.D. 369; and that it was they also who, using a tombstone (C. 723) among their material, reduced the gateway to a six-foot postern, rather in the manner of the final reconstruction of the south-west gate23 at Caernarvon. The gateway in its wider form24 is evidently part of the Constantian fortifications. There are signs, however, that this was not the first gateway on the site. The south jamb has been erected upon flagged foundations associated with an earlier fort-wall, whose footings project far beyond the Constantian wall-face: and the striking resemblance between these remains and those now discovered on the west side of the fort, allows us to conclude that they belong to a similar arrangement. The exact dimensions of the east gate at this period must, however, remain doubtful, since the robbers of the Constantian jamb removed also the earlier foundation upon which it was standing: only two stones appear to remain in position, which would fit a pier corresponding to the remains at the west.

There can thus be little doubt that the newly discovered west gate was matched by an east gate of similar plan, and that both represent the portae principales of the third-century fort, which faced southwards. When the fort was turned northwards, in the next period, the Constantian builders, preferring utility to standard planning, built a new western porta principalis in the appropriate position; but on the steep bank of the Chainley Burn, they kept the gate in the old position, where access was easier. An even more drastic disregard for the traditional convention appears at Risinghazn, where the contemporary builders supplied a new west gate in similar position, but turned the principia so as to face it; while on the east side they appear to have supplied no gate at all, because the fort25 there overlooked a marsh.
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Figure 5
The type of gateway thus rediscovered is an old one, occurring in many forts, and portrayed on Trajan's Column.26 On Hadrian's Wall it was not used for the main gates of the forts; but it is interesting to observe that it is employed for the portae quintanae, which in those forts whose praetentura juts beyond the Wall, became in effect the portae principales, for the Military Way. It is also used for every one of the milecastle gates, though many of these in the third century were reduced to pedestrian size. There can be little doubt that experience had shown this type of gate to be sufficient for traffic needs, and that in the third-century rebuilding of Vindolanda it was introduced as a matter of course, in preference to the larger twin portals less easy to defend. It is unknown what the south gate of this period was like, but, as the porta praetoria, it was the more likely to have been fitted with towers, perhaps ornate ones like those of Risingham. The north gate appears to have been totally removed when the fourth-century north gate was built, though traces of an early fort-wall have been noted27 a little to the west, and somewhat further north than the Constantian wall. Particular interest will therefore centre in the examination of the south gate, when the opportunity comes.

§6. Circular buildings below the north rampart. (Pl. xviii, xx.)

The remarkable group of buildings shown on the accompanying plan was found by chance in 1934, when the section taken through the north rampart of the Constantian fort was dug across the centre of the second from the west; the western portion of that building, and the surviving remains of its western neighbour, were uncovered in that year, while three more were excavated wholly or in part in 1935, making four in a single row, and one to the south, all opening on an alley, 14 feet wide, that separates the isolated example from the row of four. All are circular, with all internal diameter of about 14 feet, two-foot walls and a tlirce-foot doorway with stone threshold, pivot-hole and door-stop; their floors were of flags, and their roofs tiled.

Stratigraphically, they come immediately below the latter's stone wall and earth rampart-mound; the wall embodies their foundations in its footing, and the mound covers as much of them as projects south of the wall; the outlier to the south is cut through by a drain of the penultimate period of the occupation. Immediately below them, and unseparated by a destruction-layer,28 occurs a patch of flagging, extending over a drain running north and south; parallel to the drain, 7 feet to the east, is a fragment of walling and a large threshold stone, with a pivot-hole at its north end and considerable wear on the northern 3 feet of its surface. Lower still, separated from the flagging by a sterile layer of clean clay, comes a deposit containing pottery of the period Domitian-Trajan,29 associated with the sleeper-trenches of a wooden building, running north and south on a different alinement. In seeking to connect these levels with the known periods of the site's occupation, there is only one main difficulty. It is evident that the circular buildings belong to the third century; they immediately antedate the Constantian rampart, and are of the same soft sandstone as that used in the earlier principia. It is uncertain, however, whether they (like the principia) should be assigned to the time of Severus Alexander or that of Severus; and, in consequence, it is also uncertain whether the flagging on which they rest, and the associated structures, are to be connected with Severus or with the second-century occupation, initiated by Calpurnius Agricola,30 to which plentiful pottery testifies, though structural remains have not yet been identified. In passing, it must be noted that no traces of that period were found underlying the early principia; one or two pockets of pre-Hadrianic material were found, from which came two pieces of figured samian ware noticed below, but nothing more. Only further spade-work can elucidate this chronological puzzle, which leaves the upper date of the circular buildings in doubt, though they were certainly in use in the last three-quarters of the third century.

What that use was is also something of a puzzle. The buildings are recorded now in the hope that analogies, so far lacking,30a may appear. Meanwhile, some hypotheses as to the purpose of them have been discarded, and a suggestion may be made. They are not defensive towers, for their walls are too slight, and are not connected with a rampart; nor are they cook-houses, for they contained neither oven nor furnace. Their circular form must, however, have to do with their purpose; and we suggest, provisionally, that they were mill-houses. In the Roman army, corn was commonly ground by small units -- no doubt by each contubernium, as the frequent occurrence of small querns in the men's quarters suggests. But such piecemeal work was not always the practice; occasionally larger querns are found, inscribed with the name of a centuria;31 and at times corn was ground and bread prepared in larger quantities. In such a case, larger mills were required, of the type yielded by German forts and studied in detail by Jacobi.32 Near Greatchesters, too, a few miles to the west, corn was ground in a large watermill33 worked by the Haltwhistle Burn at Burnhead. These larger installations would require special accommodation, and we suggest that the circular buildings at Chesterholm would admirably suit the purpose, housing large mills, perhaps worked by slave-labour. Such an explanation has additional attraction, when it is recalled that cooking was regularly associated, in forts and fortresses, with the intervallum road, and that, at Chesterholm, we should expect to find the ovens on the adjacent east side of the fort, whence the prevailing west winds would carry the smoke away; thus, the mill-houses would not lie far away from the cooking place. Acceptance of this explanation must obviously await confirmation by the spade on this or other sites.

It should he noted that, in any case, these buildings are an intrusion in the fort to which they belong, for they lie across the line of the via decumana; it is remarkable that direct access, by the decuman gate, to the Stanegate -- here the only known line of communication -- should be blocked in this way.

§7. The early deposit.

The deposit already referred to, with wooden buildings running north and south, was opened up to the limits of the excavation on both sides of the Constantian wall, except where its examination would have involved removing the walls of the circular buildings or the north and south fragment of masonry. The northern end of the section cut in 1934 showed that this early level had been cut away, together with the north wall of the third-century fort, when the berm of the Constantian fort was formed. The berm itself is exceptionally wide, for a fort, about 20 feet along the ground. The ditch remained open until the close of the occupation, several examples of late fourth-century types of pottery coming from its upper levels. Reference has been made to the fine series of pottery that the early deposit yielded, and some of the figured samian ware is described below; besides the pottery, there were several interesting metal objects, the drawings of which are likewise reserved for publication in the next report, and a number of coins, which Mr. Percy Hedley has identified as follows:

1. Denarius of L. Cassius Longinus, circa 52 B.C.
2-3. Asses of Vespasian.
4-5. Asses, probably Flavian.
6. Dupondius of Trajan, ante A.D. 102.
7. As of Trajan, A.D. 103-11.

All seven coins were sealed by the thick layer of sterile clay to which reference has been made; in addition, nos. 2, 4 and 5 were sealed by the overlying flags; the series provides welcome confirmation of the date suggested by the pottery, for the early occupation with which the wooden buildings were associated. It is interesting to find early structures so far to the east of the ditch-system that was found and traced in part34 in 1930-1; it seems that the earliest fort on the site was larger, perhaps considerably larger, than its successors, unless (as at Mumrills35 and perhaps other Scottish sites) an annexe was placed on the better protected side of the site selected for fort and annexe.

21 AA4 viii, fig. 2, and p. 197.
22 AA1 i 209-11.
23 Wheeler, op. cit., 59, and fig. 19.
24 AA4 viii 199.
25 See above, p. 191.
26 Cichorius, Die Trajanssaule, Taf. xxxv, sc. xlvii.
27 Cf. AA4 viii 200, fig. 2, and p. 197.
28 The only piece of evidence for destruction is a large fragment of a roof-tile, that rested on the flags and partly underlay the foundation of the east wall of the second building from the west.
29 Cf. p. 220 above; the figured samian ware is discussed below, pp. 242 ff.
30 Cf. AA4 viii 190, 210.
30a It is possible that the south camp at Birrenswark may contain parallels (cf. Proc. Soc. Ant. Scot. xxxiii, 228); further excavation will be necessary to decide the point.
31 E.g. Ephemeris Epigraphica ix 11197; cf. our Proceedings, 2nd ser., vii, 96-8, from Greatchesters.
32 Cf. Blumlein, Bilder aus dem R-G. Kulturleben, 1918, p. 82.
33 AA3 v, pl. 1, also p. 222.
34 AA4 viii 202-4, ix 217-19.
35 Cf. Proc. Soc. Ant. Scot., lxiii, 500.
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March 5th, 2010, 2:20 pm #4

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Plate XIII, Fig. 1
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Plate XIII, Fig. 2
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Plate XIX, Fig. 1
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Plate XIX, Fig. 2
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Plate XX
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