After the death of Ivan Alexander in 1371 Ivan Sratsimir broke off ties with Tarnovo and even placed the archbishop of Vidin under the jurisdiction of the Patriarchate of Constantinople to demonstrate his independence. Due to its geographical position, Vidin was initially safe from attacks by the Ottoman Turks who were ravaging the Balkans to the south and Ivan Sratsimir made no attempts to assist Ivan Shishman in his struggle against the Ottomans. Only after the fall of Tarnovo in 1393 did his policy become more active and he eventually joined the crusade of the Hungarian king Sigismund. However, after the disastrous battle of Nicopolis in 1396, the Ottomans marched to Vidin and seized it. Ivan Sratsimir was captured and imprisoned in Bursa where he was probably strangled. Although his son Constantine II claimed the title Emperor of Bulgaria and at times controlled some parts of his father's realm, Ivan Sratsimir is generally regarded by historians as the last ruler of medieval Bulgaria.