By the 1500s, Ismail I of Ardabil established the Safavid Empire, with his capital at Tabriz. Beginning with Azerbaijan, he subsequently extended his authority over all of the Iranian territories, and established an intermittent Iranian hegemony over the vast relative regions, reasserting the Iranian identity within large parts of Greater Iran. Iran was predominantly Sunni, but Ismail instigated a forced conversion to the Shia branch of Islam, spreading throughout the Safavid territories in the Caucasus, Iran, Anatolia, and Mesopotamia. As a result, modern-day Iran is the only official Shia nation of the world, with it holding an absolute majority in Iran and the Republic of Azerbaijan, having there the first and the second highest number of Shia inhabitants by population percentage in the world. Meanwhile, the centuries-long geopolitical and ideological rivalry between Safavid Iran and the neighboring Ottoman Empire led to numerous Ottoman–Iranian wars.