Ikiwiki supports using several revision control systems for storing page histories.
Ikiwiki started out supporting only Subversion, but the interface ikiwiki uses to a revision control system is sufficiently simple and generic that it can be adapted to work with many systems by writing a plugin. Subversion is still a recommended choice; git is another well-tested option.
These are all the supported revision control systems:
Git
Posted Tue May 5 19:56:55 2009
mercurial
Posted Tue May 5 19:56:55 2009
tla
Posted Tue May 5 19:56:55 2009
svn
Posted Tue May 5 19:56:55 2009
monotone
Posted Tue May 5 19:56:55 2009
darcs
Posted Tue May 5 19:56:55 2009
bzr
Posted Tue May 5 19:56:55 2009
There is a page with details about how the different systems work with ikiwiki, for the curious.