The Moirae were the fates. It was believed that no one, not even the Gods and Goddesses, could escape the destiny that the Moirae created. Sophocles' play "Oedipus Rex" is one of the best examples of the disaster that comes from attempting to escape your fate.
Clotho--Spins Life's Thread
Lachesis--Measures Life's Thread
Atropos--Cuts Life's Thread