Parthia

Parthia, an ancient kingdom, forming part s of what is now northern Persia, had Hyrcania as its northern, and Bactria and Media as its eastern and western boundaries, the Iranian deserts lying to the south. Its inhabitants came from Scythia, and were subject to their neighbours until in the middle of the 3rd century B.C. Tiridates incorporated Parthia with Hyrcania. Mithradates I. (171-38 B.C.) freed himself from all dependence on Syria, and conquered Bactria, Media, and Babylonia. His successor repelled the attacks of his country's former suzerain, but Parthia soon after became tributary to the Scythians. From the middle of the 1st century B.C. till the 3rd century A.D. a long struggle was carried-on with Rome. In 218 the Emperor Macrinus was not only defeated, but obliged to pay a heavy sum to the victors. The Parthian power came to an end a few years later, when Ardashir, the Persian, conquered it.