The Kızıl Avlu (Red Basilica) was built by the Roman Empire. The temple is thought to have been used for the worship of the Egyptian gods – specifically Isis and/or Serapis, and possibly also Osiris, Harpocrates and other lesser gods, who may have been worshipped in a pair of drum-shaped rotundas, both of which are virtually intact, alongside the main temple. The immense size and lavish construction of the complex points to an extremely wealthy patron who sent a Roman architect and brick masons to Pergamon to build the temple. The most likely candidate is the emperor Hadrian himself as he is known to have been an enthusiastic sponsor of the Egyptian gods. The structure has been used as a temple, a Christian basilica, and a mosque.