They are called Parcae, because, as Varro thinks, they distributed to mankind good and bad things at their birth; or, as the common and received opinion is, because they spare nobody. They were always of the same mind, so that though dissensions sometimes arose among the other gods, no difference was ever known to subsist among these three sisters, whose decrees were immutable. To them was entrusted the spinning and management of the thread of life; Clotho held the distaff, Lachesis turned the wheel, and Atropos cut the thread.
Plutarch tells us they represented the three parts of the world - the firmament of the fixed stars, the firmament of the planets, and the space of air between the moon and the earth; Plato says they represented time past, present, and to come. There were no divinities in the pagan world who had a more absolute power than the Fates. They were looked upon as the dispensers of the eternal decrees of Jupiter, and were all of them sometimes supposed to spin the party-colored thread of each man's life. Thus are they represented on a medal, each with a distaff in her hand. The fullest and best description of them in any of the poets, is in Catullus: he represents them as all spinning, and at the same time singing, and foretelling the birth and fortunes of Achilles, at Peleus' wedding.