An open source version control system written in
<a href="http://www.haskell.org/">Haskell</a>. Distributed, easy to set up
-and serve, supports renames, and incorporates the author "Theory of Patches".
+and serve, supports renames, and incorporates the author’s "Theory of Patches".
+A distributed version control created by Linus Torvalds (also known as the
+originator and chief maintainer of the Linux kernel) after the demise of
+the BitKeeper for open-source projects. Distributed, fast, but may exhibit
+some counter-intuitive behaviours.
+Mercurial (also known as hg) is a distributed version control system written
+in Python, that aims to combine the best aspects of Git and Subversion, and
+so be fast and easy to use.