When people use the term ‘stable’ in wrestling, did it originate with the Four Horsemen, or was the term used prior to that legendary group?
Prior to the Four Horsemen, were there any significant wrestling groups that may not be well known today? Were stables uncommon prior to the 80s?
The first "official" ones were both around the same time, and predated the Horsemen. You had the Legion of Doom in Georgia/Mid-South (which was Ellering's group of the Road Warriors, King Kong Bundy and Jake Roberts in various forms) as the most notable "named" one. The one that was closest to what we'd consider a stable today, with rotating membership and a manager with a clear motivation ala Bobby Heenan's family, would have to be Jimmy Hart in Memphis in the very early 80s and his vendetta against Jerry Lawler. Hell, you could even say Bobby Heenan in the AWA all the way back into the 70s!
So no, they weren't uncommon and certainly there were significant ones before the Horsemen.