Phoebe, also known as Phoibe, was a Titan goddess of Greek mythology. Phoebe was not one of the major goddesses of the Greek pantheon, but she lives on in various literary works written throughout the years. Notably, she is credited as being the mother of Asteria and Leto, among other children.
The first Greek city-states were formed around 850 BCE (before the common era). Each worshipped one particular god or goddess as their own. One of the most widely known examples of this selective worship took place in Athens. Athenians worshipped Athena above all, but still considered themselves to be obedient to the other gods and goddesses of the Greek pantheon. Around this time, Phoebe was one of the goddesses included in the pantheon.
Phoebe was a Titan goddess. The Titans were sons and daughters of Uranus and Gaia, as told in Hesiod's "Theogony." Phoebe, the goddess of intellect, was married to Koios (an apt marriage, as Koios, or Coeus, was known as the inquirer). Their children were Asteria and Leto, as told in the "Dictionary of Greek and Roman Biography and Mythology." Leto went on to bear Artemis, Apollo, and Asteria, three better-known deities in mythology. During her reign, Phoebe held the Oracle of Delphoe, which she eventually passed on to Apollon, her grandson, acording to mythology.
Phoebe is often associated with Artemis as goddess of the moon. Although Phoebe was Artemis' grandmother, she was never actually the moon goddess. This confusion is most likely based out of their family connection. Phoebe is also one of the older goddesses of mythology; she was a sister to Kronos, from whom the younger generation (Zeus, Athena, etc.) was spawned. The lack of information on Phoebe in popular mythology stems directly from this age gap with the more "popular" deities.
Greece is a peninsula surrounded by water on three sides. This led to the seafaring aspect of ancient Greek culture. The rest of Greece is very mountainous--mountain ranges cover about three-quarters of the country. Thus, the ancient Greeks were fairly self-sustained, at least in the early parts of their history. Delphoi, the location of Phoebe's Oracle, was located North West of Athens and Thebus.
The evolution of Greek gods and goddesses can be tracked through family lineages available in various historical works of literature. Gaea and Uranus gave birth to nine children: Cronus, Rhea, Hyperion, Thea, Iapetus, Oceanus, Clymene, Coeus, and Phoebe. Eight of the nine married each other. Coeus and Phoebe were partners and parented Leto, who went on to bear Artemis and Apollo with her partner Zeus. Apollo, grandson to Phoebe, partnered with Hyria and parented Cycnus. Phoebe is, therefore, related to every god and goddess of the Greek pantheon.