It was Ptolemy I who set up not only the Museum in Alexandria, but the Serapeum, devoted to the worship of a trinity of gods which represented the result of a process of theocrasia applied more particularly to the gods of Greece and Egypt.
This trinity consisted of the god Serapis (= Osiris + Apis), the goddess Isis (= Hathor, the cow-moon goddess), and the child-god Horus. In one way or another almost every other god was identified with one or other of these three aspects of the one God, even the sun god Mithras of the Persians. And they were each other; they were three, but they were also one. They were worshipped with great fervour, and the jangling of a peculiar instrument, the sistrum, a frame set with bells and used rather after the fashion of the tambourine in the proceedings of the modern Salvation Army, was a distinctive accessory to the ceremonies. And now for the first time we find the idea of immortality becoming the central idea of a religion that extended beyond Egypt. Neither the early Aryans nor the early Semites seem to have troubled very much about immortality, it has affected the Mongolian mind very little, but the continuation of the individual life after death had been from the earliest times an intense pre-occupation of the Egyptians. It played now a large part in the worship of Serapis. In the devotional literature of his cult he is spoken of as "the saviour and leader of souls, leading souls to the light and receiving them again." It is stated that "he raises the dead, he shows forth the longed-for light of the sun to those who see, whose holy tombs contain multitudes of sacred books"; and again, "we never can escape him, he will save us, after death we shall still be the care of his providence."
The ceremonial burning of candles and the offering of ex-votos, that is to say of small models of parts of the human body in need
- Legge, Forerunners and Rivals of Christianity.