 Once the first part was completed, Smederevo Fortress quickly became an important connection between the Balkans and central Europe.Shortly after it was built, the city reached its peak importance as a religious, commercial, and trade center, at which point it was populated mainly by Serbs and colonies of merchants, primarily from Dubrovnik.Around the same time, the relics of Saint Luke the Evangelist, who became the patron saint of Smederevo, were brought and stored in the church in the fortress.