In the last months of 330 BC, the Macedonian king Alexander the Great conquered Aria in pursuit of the last Persian leader, Bessus. He is credited with the building a town called Alexandria (modern Herat), but this was probably a Persian center of government.
After Alexander's death (in 323), Aria became a stable part of the Seleucid Empire -ruled by a Macedonian dynasty- for more than half a century. However, after 250, the neighboring countries Bactria and Parthia became independent from their Macedonian overlords. Aria became part of the new Bactrian kingdom, although the Seleucid king Antiochus III managed to extend his realm to the east between 208 and 190. His son Antiochus IV send a general, Eucratides, to do the same in 167, but the Parthian king Mithridates I outsmarted him and seized almost all Afghanistan. From now on, Aria was part of the Parthian Empire.