ISIS, the most famous of the Egyptian goddesses. She was of human form, in early times distinguished only by the hieroglyph of her name upon her head. Later she commonly wore the horns of a cow, and the cow was sacred to her; it is doubtful, however, whether she had any animal representation in early times, nor had she possession of any considerable locality until a late period, when Philae, Behbet and other large temples were dedicated to her worship. Yet she was of great importance in mythology, religion and magic, appearing constantly in the very ancient Pyramid texts as the devoted sister-wife of Osiris and mother of Horus. In the divine genealogies she is daughter of Keb and Nut (earth and sky). She was supreme in magical power, cunning and knowledge.
Isis was identified with Demeter by Herodotus, and described as the goddess who was held to be the greatest by the Egyptians; he states that she and Osiris, unlike other deities, were worshipped throughout the land. The importance of Isis had increased greatly since the end of the New Kingdom. The great temple of Philae was begun under the XXXth Dynasty; that of Behbet seems to have been built by Ptolemy II. The cult of Isis spread into Greece with that of Serapis (q.v.), early in the 3rd century B.C. In
Egypt itself Isea, or shrines of Isis, swarmed. At Coptos Isis became a leading divinity on a par with the early god Min. About 8o B.C. Sulla founded an Isiac college in Rome, but their altars within the city were overthrown by the consuls no less than four times in the decade from 58 to 48 B.C., and the worship of Isis at Rome continued to be limited or suppressed by a succession of enactments which were enforced until the reign of Caligula. At Philae the temple of Isis was frequented until the middle of the 6th century when the last remaining shrine of Isis was finally closed.
See G. Lafaye, art. "Isis" in Daremberg et Saglio, Dictionnaire des antiquites (i900) ; id. Hist. du culte des divinites d'Alexandrie hors de l'Egypte (1883) ; Meyer and Drexler, art. "Isis" in Roscher's Lexicon der griech. and rom. Mythologie (1891-92) (very elaborate) ; E. A. W. Budge, Gods of the Egyptians, vol. ii. ch. xiii.; Ad. Rusch, De Serapide et Iside in Graecia cultis (dissertation) (Berlin, 1906). (The author especially collects the evidence from Greek inscriptions earlier than the Roman conquest ; he contends that the mysteries of Isis were not equated with the Eleusinian mysteries.)