Persis (, Persís; Old Persian: 𐎱𐎠𐎼𐎿, Parsa; , Pârs), also called Persia proper, is the Fars region, located to the southwest of modern-day Iran, now a province. The Persians are thought to have initially migrated either from Central Asia or, more probably, from the north through the Caucasus. They would then have migrated to the current region of Persis in the early 1st millennium BC. The country name Persia was derived directly from the Old Persian Parsa. Achaemenid Empire The ancient Persians were present in the region of Persis from about the 10th century BC. They became the rulers of the largest empire the world had yet seen under the Achaemenid dynasty which was established in the late 6th century BC, at its peak stretching from Thrace-Macedonia, Bulgaria-Paeonia and Eastern Europe proper in the west, to the Indus Valley in its far east. The ruins of Persepolis and Pasargadae, two of the four capitals of the Achaemenid Empire, are located in Fars. Alexandrian Empire The Achaemenid Empire was defeated by Alexander the Great in 330 BC, incorporating most of their vast empire. Several Hellenistic satraps of Persis are known (following the conquests of Alexander the Great) from circa 330 BC, especially Phrasaortes, who ruled from 330 to 324 BC; Oxines, who usurped his position and was then executed by Alexander; and the Macedonian general Peucestas, who learned the Persian language and followed local customs, implementing a persophile policy. Peucestas retained the satrapy of Persis until the Battle of Gabiene (316 BC), after which he was removed from his position by Antigonus. A short period of Antigonid rule followed, until Seleucus took possession of the region in 312 BC. Seleucid Empire When the Seleucid Empire was established, it possibly never extended its power beyond the main trade routes in Fars, and by the reign of Antiochus I or possibly later, Persis emerged as a state with a level of independence that minted its own coins. "Frataraka" Governors of the Seleucid Empire Several later Persian rulers, forming the Frataraka dynasty, are known to have acted as representatives of the Seleucids in the region of Fārs. They ruled from the end of the 3rd century BC to the beginning of the 2nd century BC, and Vahbarz or Vādfradād I obtained independence circa 150 BC, when Seleucid power waned in the areas of southwestern Persia and the Persian Gulf region. Kings of Persis, under