Twelve years ago, on May 19th 1998, I officially started to work on GNOME by importing LibGTop into GNOME CVS.
In the meantime, GNOME has first migrated to SVN and then to GIT, but that revision still exists:
commit 33cdc01c1db3a1cafaeb63e50247072b82ef49ea in GIT.
Time to celebrate the anniversary :-)