In the next centuries, Armenia was in the Persian Empire's sphere of influence during the reign of Tiridates I, the founder of the Arsacid dynasty of Armenia, which itself was a branch of the Parthian Empire. Throughout its history, the kingdom of Armenia enjoyed both periods of independence and periods of autonomy subject to contemporary empires. Its strategic location between two continents has subjected it to invasions by many peoples, including Assyria (under Ashurbanipal, at around 669–627 BC, the boundaries of Assyria reached as far as Armenia and the Caucasus Mountains), Medes, Achaemenid Empire, Greeks, Parthians, Romans, Sasanian Empire, Byzantine Empire, Arabs, Seljuk Empire, Mongols, Ottoman Empire, the successive Safavid, Afsharid, and Qajar dynasties of Iran, and the Russians.