Complex sentence: Pioneerof the Nile (foaled May 5,2006 in Kentucky) is an American Thoroughbred racehorse who was the second place finisher in the 2009 Kentucky Derby and is the sire of 2015 Triple Crown winner American Pharoah.
Split into simpler sentences: Pioneerof the Nile (foaled May 5,2006 in Kentucky) is an American Thoroughbred racehorse who was the second place finisher in the 2009 Kentucky Derby. He is the sire of 2015 Triple Crown winner American Pharoah.