Mailing the story:

Git maintainer Junio Hamano [story] announced the official 1.0.0 release ofgit, the directory content manager originally written by Linus Torvalds and used to manage the Linux kernel source tree. Junio notes that there haven't been any big changes recently, "

Development of the git directory content manager was begun by Linus Torvalds in early April of 2005 [story], quickly following the announcement that BitKeeper would no longer be freely available to kernel developers [story]. Git rapidly evolved with the help of an active developer community, quickly enough that when the 2.6.12 kernel was released two months later it was already being managed by git [story].