Original: The code was officially forked from Mandrake 9.2 into an independent project in 2003. After three years of continuous development, the developers took advantage of further development in (the renamed) Mandriva, and forked the code again late in 2006 for PCLinuxOS 2007.
Simplified: The code was officially forked into an independent project in 2003, but after three years of contiguous development, the devs took advantage of further development in (the renamed) Mandriva, and forked the code again for PCLinuxOS 2007.