This change, occurring between roughly 2000 BCE and 700 CE, has long been celebrated as a huge step forward for humankind—the “axial transformation”—propelling us from the unseemly worship of savage beasts to the refined and dignified adoration of a god who is both perfect and perfectly good.
But it was a tragic demotion for animals. The axial religions determined that some of them were ritually “unclean” and reclassified all of them as the inferiors of humans.
Source: The Animal Cure