Achaemenid traditions, rock-relief images of Arsacid rulers were carved at Mount Behistun, where Darius I of Persia (r. 522–486 BC) made royal inscriptions. Moreover, the Arsacids claimed familial descent from Artaxerxes II of Persia (r. 404–358 BC) as a means to bolster their legitimacy in ruling over former Achaemenid territories, i.e. as being "legitimate successors of glorious kings" of ancient Iran. Artabanus II named one of his sons Darius and laid claim to Cyrus' heritage. The Arsacid kings chose typical Zoroastrian names for themselves and some from the "heroic background" of the Avesta, according to V.G. Lukonin. The Parthians also adopted the use of the Babylonian calendar with names from the Achaemenid Iranian calendar, replacing the Macedonian calendar of the Seleucids. Religion The Parthian Empire, being culturally and politically heterogeneous, had a variety of religious systems and beliefs, the most widespread being those dedicated to Greek and Iranian cults. Aside from a minority of Jews and early Christians, most Parthians were polytheistic. Greek and Iranian deities were often blended together as one. For example, Zeus was often equated with Ahura Mazda, Hades with Angra Mainyu, Aphrodite and Hera with Anahita, Apollo with Mithra, and Hermes with Shamash. Aside from the main gods and goddesses, each ethnic group and city had their own designated deities. As with Seleucid rulers, Parthian art indicates that the Arsacid kings viewed themselves as gods; this cult of the ruler was perhaps the most widespread. The extent of Arsacid patronage of Zoroastrianism is debated in modern scholarship. The followers of Zoroaster would have found the bloody sacrifices of some Parthian-era Iranian cults to be unacceptable. However, there is evidence that Vologases I encouraged the presence of Zoroastrian magi priests at court and sponsored the compilation of sacred Zoroastrian texts which later formed the Avesta. The Sasanian court would later adopt Zoroastrianism as the official state religion of the empire. Although Mani (216–276 AD), the founding prophet of Manichaeism, did not proclaim his first religious revelation until 228/229 AD, Bivar asserts that his new faith contained "elements of Mandaean belief, Iranian cosmogony, and even echoes of Christianity ... [it] may be regarded as a typical reflection of the mixed religious doctrines of the late Arsacid period, which the Zoroastrian orthodoxy of the Sasanians was soon to sweep away." There is scant archaeological evidence for the spread of Buddhism from the Kushan Empire into Iran proper. However, it