The Macedonian Ptolemies, who ruled Egypt in the wake of Alexander, sought to become pharaonic god-kings to their subjects. By merging Greek and Egyptian elements in the Serapis cult, and building temples to the ancient gods, they achieved what Assyrian and Persian invaders before them never could-they became spiritual successors of the pharaohs. Many of the great temples of Upper Egypt date to Ptolemaic times. The conquerors, however, may have been more influenced than influencing; the mystery cults of Osiris, Isis, and Horus spread throughout the Hellenistic world and later throughout the Roman Empire.