The Sacred Bull Apis or Hapis is thought to be the first god worshiped in Egypt, originating has a fertility deity connected to agriculture. The worship of an Apis Bull began during the first dinasty and it was part of a ritual sacrifice symbolizing the rebirth and the renewal of life (crops). Later in time it was served as a mediator between humans and other powerful dieties. Now the bull is no more - lets rejoice that maybe it is because we found a more powerful intermediary to reach for a numinous level of counciousness.
The worship of the bull was also observed in Indo-Europeans cinvilizations such as the Minoans of Crete and the Hindu of the Indus Valley, both of wich can still be observed today.