Double Dynamite from Magnificent Marvel! 1972 house ad.
This is it—with this advertisement, the Marvel Age truly began. The first branding of the “Marvel Comics Group.” The first mention of “The House of Ideas.” The first time this many characters from different titles shared a page.
From Fantastic Four #14, published February 12, 1963.
Evel Knievel #1, 1974, cover by John Romita and Joe Sinnott