godfather of the free software movement
But I disagree with the having Stalman as the locus of free software. There was free software before him (BSD, etc) and will be free software after him. Maybe capitalize it right. Yeah, he created the Free Software Foundation. Just call it that.. godfather of the FSF.
Stalman has done a lot, but sometimes his ideas get in the way of actual software. Hurd? after decades still not shipped. gcc? Got out of hand until it got taken over by egcs. Was also the "Cathedral" in "The Cathedral and the Bazaar" as the example of what NOT to do. emacs? Witness the hassle with xemacs and emacs.
I believe Stallman is credited for this because the average user never heard of Open Source or Free Software until the arrival of the GPL and its enabling of systems built with the Linux kernel and GNU userland. Now that those have arrived and taken off, the corporate investment in open source software has increased tremendously and most people have at least heard of Linux even if they don't personally use it. Lots more people at least use some kind of open source software even if they are not programmers and don't appreciate what this means, e.g. Firefox, much of Android and its apps, many servers run Linux, etc. These things are all based around the GPL.
One could speculate that what the movement really needed was more ubiquitous Internet access, of course, but for whatever reason, FOSS and similar ideas were completely unknown to average users until the GPL took off. That's why Stallman receives this kind of credit. You also have to admire a guy when most criticisms against him boil down to "you are too much of a purist" which can be restated as "you are too consistent [for my liking/convenience] with your stated principles". He contributed not just a license that really facilitated worldwide collaboration, but also a consistent, well-articulated set of principles based on his best understanding of freedom; and he actually got many people to listen to them. That's an accomplishment all by itself.