Temple of Hercules Project, which ACOR began in 1990, involved the excavation and partial reconstruction of the Roman temple, one of the principal monuments of Amman during the classical period. The project was funded by USAID and carried out by ACOR and the Department of Antiquities of Jordan. The first volume, written by Dr. Chrysanthos Kanellopoulos, documents the architectural elements of the temple. It contains a wealth of photographs and drawings detailing all aspects of the Great Temple construction, excavation and preservation. The great Roman temple on the Amman Citadel, or Jebel al-Qala, is popularly known as the Temple of Hercules and can be dated to the term of the Roman governor Geminius Marcianus (A.D.161-166). Excavations were first conducted on the Citadel in the 1930s by Italian archaeologists.