I think you probably mean mercurial (hg) which is indeed written in python. Subversion (svn) is written in C. Mercurial actually wasn't a bad choice at the beg

I think you probably mean mercurial (hg) which is indeed written in python. Subversion (svn) is written in C. Mercurial actually wasn't a bad choice at the beginning of the DVCS era on Windows as git didn't work well on that platform initially.