Persia is a region of Central Asia, corresponding to the present-day country of Iran. Persia was renowned for its status as a dominant early civilization from 550 BC to 651 AD (with some interruptions, including Alexander the Great's Greek rule and Seleucid rule), and the region was the home of Zoroastrianism. From 633 to 654, Persia was conquered by the Islamic Rashidun Caliphate, and Persia was converted to Islam; it would later become the largest Shia country in the world. Today, Persia is known as the "Islamic Republic of Iran".