By the 5th century BC the Kings of Persia were either ruling over or had subordinated territories encompassing not just all of the Persian Plateau and all of the territories formerly held by the Assyrian Empire (Mesopotamia, the Levant, Cyprus and Egypt), but beyond this all of Anatolia and Armenia, as well as the Southern Caucasus and parts of the North Caucasus, Azerbaijan, Uzbekistan, Tajikistan, all of Bulgaria, Paeonia, Thrace and Macedonia to the north and west, most of the Black Sea coastal regions, parts of Central Asia as far as the Aral Sea, the Oxus and Jaxartes to the north and north-east, the Hindu Kush and the western Indus basin (corresponding to modern Afghanistan and Pakistan) to the far east, parts of northern Arabia to the south, and parts of northern Libya to the south-west, and parts of Oman, China, and the UAE.