The offspring of Gaea the earth and Uranus the heavens became known as the Titans of Myth. Among them were Rhea and Cronus, Titans of the Earth. Although the Titans of Myth enjoyed god-like status, Gaea had other, less attractive members of her brood, whom Uranus banished to the pits of Tartarus.
Gaea persuaded Cronus to kill Uranus and then release her captice brood. Cronus accomplished the first part of his mission, but then invited Rhea and the rest of the Titans of Myth to join him in the paradise of a subjugated Earth.
Cronus and Rhea went on to have several children, but because Cronus feared an ancient oracle that foretold his own children would rise against him, he ate each one at birth - apart from Zeus, whom Rhea saved.
Once he reached manhood, Zeus released his siblings and the underground brood, overthrew his father and banished the Titans of Myth - Rhea left with the Titans - to the stone pillars of Tartarus. Many thousands of years later, Thia and Hyperion managed to free themselves, and with the help of Donna Troy, released Rhea and the other Titans of Myth. Rhea now joined her husband in an assault on Mount Olympus, though it grieved her to battle her own son.
After two epic battles, during which some of the Titans of Myth were slain by an insane Thia, Zeus invited the survivors to go and live with him in peace within Mount Olympus. Rhea and the others accepted.
Infant Donna Troy was saved from a fire by the Titan Rhea, who brought her to New Chronus, where she was gifted with amazing abilities. To teach humility, The Titan gods sent Donna back to earth at age 13 in the care of the Amazons (who, remember, would worship the Titan of Myth like gods). Queen Hippolyta adopted Donna as her daughter making her Diana's (Wonder Woman) adopted little sister. So Donna spent half her life with the Titans of Myth, and the other half with the Amazons. Donna then became Wonder Girl, Later She takes on the code name Troia, which is another way of saying Troy in Greek, or just Donna Troy.