The Serapeum of Saqqara is a serapeum located north west of the Pyramid of Djoser at Saqqara, a necropolis near Memphis. It was the burial place of the Apis bulls, living manifestations of the god Ptah. It was believed that the bulls became immortal after death as Osiris Apis, shortened to Serapis in the Hellenic period. The most ancient burials found at this site date back to the reign of Amenhotep III.

• http://en.wikipedia.org/wiki/Serapeum of Saqqara