Battle of Chaldiran
When Sultan Selim ascended to the Ottoman throne in 1512, relations between the Ottoman Empire and the Safavid dynasty changed radically. Selim I gained the position of sultan after a power struggle with his brothers. He eliminated his brothers, who were rivals for the throne, one after the other, and one of them fled to Ismail I of the Safavid dynasty. Furthermore, Selim ruled Trabzon for nearly 25 years from 1487 and was based in Trabzon to fight the Safavid invasion. That experience also contributed to Selim's conviction that the Safavid threat was the biggest problem for the Ottoman Empire. In 1514, he launched a campaign against the Safavids against Shah Ismail to conquer eastern Anatolia, including Erzurum and Erzincan.