Herodotus, The Persian Wars — Book II (1920)
“ All Egyptians sacrifice unblemished bulls and bull-calves; they may not sacrifice cows; these are sacred to Isis. For the images of Isis are in woman’s form, horned like an ox, as the Greeks picture Io, and cows are held by far the most sacred of all beasts of the herd by all Egyptians alike. For this reason no Egyptian man or woman will kiss a Greek man, or use a knife, or a spit, or a caldron belonging to a Greek, or taste the flesh of an unblemished ox that has been cut up with a Greek knife. ”
