When Godzilla and Kong square off in the imaginatively titled Godzilla vs. Kong, it won’t be the first time they’ve shared the screen. 50 years ago, King Kong and Godzilla battled across Tokyo in the also-creatively named King Kong vs. Godzilla. And while that was the origin of their feud, even that film was far from the first time two marquee movie characters joined forces for a shared sequel.

Decades before Marvel made their cinematic universe, resourceful studios started combining disparate film series into mega-franchises. In most cases, mega-box-office receipts soon followed. (Creative success, as we’ll see, proved slightly more elusive.) The shift from King Kong vs. Godzilla to Godzilla vs. Kong might not seem like a large one, but the concept of a crossover movie has evolved and expanded significantly over the decades. These ten key titles chart that evolution.

Gallery — The Most Ridiculous Promo Photos We’ve Ever Seen:

More From ScreenCrush