Penn excavations at Giza began in 1915 under the direction of University Museum Egyptian Section Curator Clarence Fisher and focused on the area known as the "minor cemetery." This excavation produced important information on the arrangement of Old Kingdom (2625-2130 B.C.) mastaba tombs and the mortuary cults of their owners. In the 1970's the University Museum renewed work at Giza as a sponsor of the Giza Mastabas Project, under the direction of David O'Connor, Egyptian Section Curator-in-Charge, and William K. Simpson. This work has resulted in several volumes providing information about tombs in the Giza Necropolis.