According to Greek Mythology, who was the mother of all Titans?

In Greek mythology, Gaia is the ancestral mother of Uranus (the sky), from whose sexual union she bore the Titans (themselves parents of many of the Olympian gods), the Cyclopes, and the Giants; as well as of Pontus (the sea), from whose union she bore the primordial sea gods. Her equivalent in the Roman pantheon was Terra.

After Chaos, "wide-bosomed" Gaia (Earth) arose to be the everlasting seat of the immortals who possess Olympus above. And after Gaia came "dim Tartarus in the depth of the wide-pathed Earth", and next Eros the god of love. Hesiod goes on to say that Gaia brought forth her equal Uranus (Heaven, Sky) to "cover her on every side". Gaia also bore the Ourea (Mountains), and Pontus (Sea), "without sweet union of love" (i.e., with no father). Afterwards with Uranus, her son, she gave birth to the Titans.