A simplified guide to the main Greek gods, with their Roman names.

The Olympian Gods led by Zeus were not the "oldest" gods of the Greeks.  The oldest of the gods, ruled by Uranus and Gaea, were Zeus' grandparents.  Zeus's father, Kronos [Roman name= Saturn], led a group of gods called the Titans who overthrew Uranus.  Kronos then became the ruler of the gods.  Zeus was one of his children, and led the Olympians (Kronos' other children) in overthrowing the Titans.  For more, and for more on each of these gods, take a look at the entries at Wikipedia:  http://en.wikipedia.org/wiki/Twelve_Olympians