I'm aware of many version control systems: CVS, SVN, TFS etc...
I've googled for the very first "revision control/version control system" and seen various conflicting answers.
When was source control invented? Who invented it? What was it called?
Here is a pretty decent timeline of the major players in video form (no sound).
It suggests that SCCS was first, by a margin of about 9 years.
There is a lot missing off there though, as evidenced by this blog and the resulting comments.
In 1981, I worked a summer job at Charter Information in Austin TX. They were formerly Commercial Information Corporation of Woburn MA. They ran a Xerox Sigma 6 that had been field-upgraded to a Sigma 7. They used a thing called SPUD (Source Program Update) for source code control. It was tape-based.
I routinely mounted the "bicentennial SPUD tape" and worked on a mod deck for a piece of code on that tape. It was called the "bicentennial SPUD tape" because it was written in 1976. They had older tapes, indicating that SPUD went back farther than 1976.
While a student at UT Austin (1973-1981), I ran up against MODIFY and UPDATE, two source code control programs from Control Data Corporation for the CDC 6600 and later mainframes. I do not know when they first came out, but I suspect they came out not long after the 6600, which (if memory serves me) came out in the late 1960s.
I suspect that IBM had something well before anyone else did, but I have no knowledge whatsoever of IBM mainframe history, and I like it that way.