I did a paper on the extent of human sacrifice in the ancient world. There is overwhelming evidence in the pottery and written documents of virtually every culture around the Med. that human sacrifice was used at some time in their history.
Everyone seems cool with the idea that our revered Western culture used animal sacrifice, but recoils at the possibility of human sacrifice by our civilized forebears.
Actually, the use of animals was probably just a later substitution as the cultures became a little more sophisticated and figured out they could “fool” the Gods with lesser animals.
Animal sacrifice is much older; human sacrifice was used when the situation seemed to suggest that an animal sacrifice wouldn’t get it done. Blegen’s discovery of a Linear B archive on the first morning he dug at Pylos happily followed Ventris’ discovery that the text concealed Greek, a possibility brushed off by Linear B’s discoverer, Arthur Evans. On what was apparently the last tablet in the Pylos archive was a scrawl of Linear B recording that two human sacrifices were being made, one man and one woman. The last information on the tablet was that troops were being sent. From the same period there is the Iliad’s account of human sacrifice.
Of course, cannibalism has been practiced for a really long time, though it’s a judgment call whether that was ever considered a religious rite.