Well, Philip was attending his daughter's wedding. There he was stabbed to death and his son, Alexander,was then named king.
phillip II of macedon died @ age 33
He could be considered important for a number of reasons, but probably the most popular is that he is the father of Alexander the Great. Philip's own military conquests were quite notable, though...
Pausanias of Orestis
Olympias
Philip II of Macedon (382 BC-336 BC), the king