Many Greek heroes were half-mortal children of the Olympians, the Greek gods.  Zeus was the most notorious philanderer in the Greek pantheon and sired many of the gods themselves -- and some of the most famous heroes of Greek mythology: Heracles, Perseus, the twin Argonauts Castor and Pollux.  These heroes accomplished amazing tasks because of their divine heritage, but often faced divine wrath when the gods fought amongst themselves, as they often did, striking out at the children of their enemies.