the site had been venetian and genoese colonies before the second half of the 15th century. a town named tana served as major transit point for trafficking between west and east. tana was occupied by the ottoman empire in 1471. the ottomans founded an enormous fortress there. it consisted of a stone wall with 11 towers around a hill. the faubourg was separated by a moat and ramparts. the fortress' garrison was armed with 200 cannons.