Theodosiopolis repelled many attacks and military campaigns by the Seljuks and Georgians (the latter knew the city as Karnu-Kalaki) until 1201 when the city and the province was conquered by the Seljuk sultan Süleymanshah II. Erzen-Erzurum fell to the Mongol siege in 1242, and the city was looted and devastated. After the fall of the Sultanate of Rum in early 14th century, it became an administrative province of the Ilkhanate, and later on the city was under Empire of Trebizond occupation for a while around the 1310s. Then became part of the Çoban beylik, Black Sheep Turkmen, empire of Timur Lenk and White Sheep Turkmen. It subsequently passed to Safavid Persia, until the Ottomans under Selim I in 1514 conquered it through the Battle of Chaldiran. During Ottoman imperial rule, the city served as the main base of military power in the region.