1911 Encyclopædia Britannica/Necessitas
NECESSITAS (Gr. Ἀνάγκη), in Orphic theology, the personification of absolute necessity. She appears as the mother of the Moerae (Fates), as the wife of Demiurgus (Fashioner of the World) and mother of Heimarmenē (Destiny). Her power is irresistible, even greater than that of the gods; to her was due the strife (battles with Titans, Giants) that raged amongst them of old, before the rule of love began; the world revolves round the spindle, which she holds in her lap. According to the Egyptian theory, she is one of the four deities present at the birth of every human being, her companions being the Daemon (guardian spirit), Tyche (Fortune) and Eros. On the citadel of Corinth there was a temple sacred to her and Bia (Violence), which none were permitted to enter. The Roman Necessitas is represented in the well-known ode of Horace (i. 35) as the forerunner and companion of Fortuna, holding in her brazen hand huge nails, a clamp and molten lead, symbolical of fixedness and tenacity.
See Plato, Rep. 616 c, Symp. 195 c, 197 B; Macrobius, Saturnalia, i. 19; Pausanias ii. 4. 6.