Mad Dog,Jul 29 2013 wrote: Defenders #8-9
Crossover, is this one of the earliest crossovers of this nature?
For a segmented crossover between two TEAMS, I think it may very well be.
With the formula of :
Part 1 is in Title A
Part 2 is in Title B
Part 3 is in Title A, so on...
The original Defenders/Marvel Feature stories kinda' went like that, but each part wasn't exactly essential.
Sub-Mariner and Iron-Man each had non-team-up stories that stretched across five titles in the late 60's.
First Part, each ended with a "to be continued":
-Tales to Astonish (Sub-Mariner story)
-Tales of Suspense (Iron Man story)
Second Part, each story above continued into:
Iron Man/Sub-Mariner #1
Third Part, each story then continued into their solo books:
Iron Man #1
They also pulled the same thing off with Hulk and Captain America (the other halves of "Astonish" and "Suspense") going into their own books, but saved a step by not having the one-shot.
The Kree-Skrull War in the early 70's (circa Avengers issues #95 or so) continued from "Avengers" directly into issues of "Captain Marvel", but it wasn't two separate teams. The Defenders/Avengers cross-over took the ol' Gardner Fox JLA/JSA formula of two teams meeting up, then breaking off into tandems, but split it across two separate titles.