In the Osiris myth, the youthful Horus loses an eye in his battle with Set.

This eye, the symbol of sacrifice, became, next to the sacred beetle, the most common talisman of the country, and all museums are rich in models of the Horus eye in glass or stone.
"When alchemy or chemistry, which had its cradle in Egypt, and derived its name from Khami, an old title for this country, passed to the hands of the Greeks, and later of the Arabs, this sign passed with it.

It was also adopted to some extent by the Gnostics of the early Christian church in Egypt.

In a cursive form it is found in mediaeval translations of the works of Ptolemy the astrologer, as the sign of the planet Jupiter.

As such it was placed upon horoscopes and upon formula containing drugs made for administration to the body, so that the harmful properties of these drugs might be removed under the influence of the lucky planet.