Dave Bartruff/Corbis

The Persian king Darius I (522–486 B.C.), probably depicted in this relief carving from Persepolis, came to power during a period of turmoil following the death of King Cambyses, son of the Persian empire’s founder, Cyrus the Great (559–530 B.C.). Lacking a clear claim to the throne, Darius was forced to legitimize his rule in other ways, by leaving monumental inscriptions and building his own city (see “Why Darius Built Persepolis,”). He also “invented” the Achaemenid dynasty-claiming that he and Cyrus both descended from a seventh-century B.C. king named Achaemenes.