xHarbour (extended Harbour) was started by Ron Pinkas late 2001 as a fork off of the Harbour Project in which he was one of the leading developers. xHarbour was established to provide a more aggressive alternative to the conservative style of development in the Harbour Project.
The Harbour Project was launched in December 1999 by Antonio Linares. Naturally, the developers of the Harbour Project have contributed large amounts to xHarbour, since xHarbour originated from the Harbour code base. You can find a list of those developers at SourceForge. The Harbour Project is still active, too - and some developers work on both projects.
In its short life, xHarbour already established itself as the favorite tool of the xbased programmer in general, and has attracted many loyal users.
Why two Projects?
Ron started the project with this sentence [source: sourceforge ]:
"As a result of some conflicts regarding current and future development direction, xHarbour will offer an alternative for those interested in a more aggressive & less conservative approach."
One major benefit of Open Source - it encourages the natural evolution process!