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 Sun Feb 10 23:46:47 2008
mercurial
Posted Sun Feb 10 23:46:47 2008
tla
Posted Sun Feb 10 23:46:47 2008
svn
Posted Sun Feb 10 23:46:47 2008
monotone
Posted Sun Feb 10 23:46:47 2008
bzr
Posted Sun Feb 10 23:46:47 2008
There is a page with details about how the different systems work with ikiwiki, for the curious.