The Serapeum of Saqqara was the ancient Egyptian burial place for sacred bulls of the Apis cult at Memphis. It was believed that the bulls were incarnations of the god Ptah, which would become immortal after death as Osiris-Apis. a name which evolved to Serapis (Σέραπις) in the Hellenistic period, and Userhapi (ⲟⲩⲥⲉⲣϩⲁⲡⲓ) in Coptic. It is part of the Saqqara necropolis, which includes several other animal catacombs, notably the burial vaults of the mother cows of the Apis. Over a timespan of approximately 1400 years, from the New Kingdom of Egypt to the end of the Ptolemaic Period, at least sixty Apis are attested to have been interred at the Serapeum. For the earliest burials, isolated tombs were constructed. As the cult gained importance, underground galleries were dug that connected subsequent burial chambers. Above ground, the main temple enclosure was supplemented by shrines, workshops, housing and administrative quarters.