In the 6th century BC, Cyrus the Great of neighbouring Persia defeated the Neo-Babylonian Empire at the Battle of Opis and Iraq was subsumed into the Achaemenid Empire for nearly two centuries. The Achaemenids made Babylon their main capital. The Chaldeans and Chaldea disappeared at around this time, though both Assyria and Babylonia endured and thrived under Achaemenid rule (see Achaemenid Assyria). Little changed under the Persians, having spent three centuries under Assyrian rule, their kings saw themselves as successors to Ashurbanipal, and they retained Assyrian Imperial Aramaic as the language of empire, together with the Assyrian imperial infrastructure, and an Assyrian style of art and architecture.