The north east of Syria was a part of Achaemenid Assyria (Athura) between 546 and 332 BC, then to Seleucid Syria (312-150 BC), when the name Syria which was originally a 9th-century BC Indo-European corruption of Assyria and had hitherto referred only to Assyria itself, also became applied to a region long known as Aramea/Eber Nari - in other words what is today modern Syria. During the Parthian Empire (150 BC-224 AD) and early Sassanid Empire (224 -650 AD) (when the land was renamed Assuristan) a number of Neo-Assyrian kingdoms arose, and parts of north east Syria became a part of the Neo-Assyrian state of Osroene until the mid 3rd century AD. Christianity became established amongst the Assyrians as early as the 1st century AD, and the region of Athura became the birthplace of Eastern Rite Christianity and Syriac literature, with the Assyrian Church of the East and Syriac Orthodox Church being founded in the region.