SDL was developed between 1998 and 2001 by Sam Lantinga, the chief programmer of the software company Loki Games. In 2002 the company got bankrupt, but Lantinga went on developing SDL. So it got updated continuously until today.
In August 2013 the successor SDL 2.0 has been released. SDL 2.0 introduces a lot of new features which allow development of high performance applications using up-to-date technologies.
Although the original library isn’t written in Pascal, fortunately the SDL 2.0 headers got translated to Pascal by Tim Blume and others, so the SDL 2.0 library is usable for Pascal developers as well.