Cronus was the Titan god of time who overthrew his father Uranus. Cronus married his sister Rhea but feared his children would overthrow him, so he ate each child as they were born. Rhea saved Zeus by substituting a stone. Zeus grew up and tricked Cronus into vomiting up his siblings. Zeus then led the gods against Cronus and the Titans in battle, freeing the Cyclopes and Hecatoncheires to aid him. With their help, Zeus defeated the Titans and imprisoned them in Tartarus, except Atlas who was punished to hold up the sky.