showcase that divination in the form of astrology and extispicy (studying the entrails of dead animals) were important parts of the Assyrian religion since they were believed to be means through which deities communicated with the mortal world. Unlike many other ancient empires, the Neo-Assyrian Empire did at its height not impose its culture and religion on conquered regions; there were no significant temples built for Ashur outside of northern Mesopotamia. In the post-imperial period, after the fall of the Neo-Assyrian Empire, the Assyrians continued to venerate Ashur and the rest of the pantheon, though without the Assyrian state, religious beliefs in many parts of the Assyrian heartland diverged and developed in different directions. From the time of Seleucid rule over the region (4th to 2nd century BC) onward, there was a strong influence of the ancient Greek religion, with many Greek deities becoming syncretized with Mesopotamian deities. There was also some influence of Judaism, given that the kings of Adiabene, a vassal kingdom covering much of the old Assyrian heartland, converted to Judaism in the 1st century AD. In the 1st century BC onward, as a frontier region between the Roman and the Parthian empires, Assyria was likely highly religiously complex and diverse. Under Parthian rule, both old and new gods were worshipped at Assur. As late as the time of the city's second destruction in the 3rd century AD, the most important deity was still Ashur, known during this time as Assor or Asor. Worship of Ashur during this time was carried out in the same way as it had been in ancient times, per a cultic calendar effectively identical to that used under the Neo-Assyrian Empire 800 years prior. The ancient Mesopotamian religion persisted in some places for centuries after the end of the post-imperial period, such as at Harran until at least the 10th century (the "Sabians" of Harran) and at Mardin until as late as the 18th century (the Shamsīyah). Christianity The Church of the East developed early in Christian history. Though tradition holds that Christianity was first spread to Mesopotamia by Thomas the Apostle, the exact timespan when the Assyrians were first Christianized is unknown. The city of Arbela was an important early Christian center; according to the later Chronicle of Arbela, Arbela became the seat of a bishop already in AD 100, but the reliability of this document is questioned among scholars. It