Early reign and Hungarian invasion Ivan Sratsimir was proclaimed emperor in Vidin in 1356 and began to use the title
Emperor of Bulgarians and Greeks, as his father. In order to secure the alliance of
Wallachia, he married his first cousin
Anna, the daughter of the Wallachian voivode
Nicholas Alexander, in 1356 or 1357, He ruled with the tacit consent of his father for around ten years until 1365 when the Hungarian king
Louis I, who styled himself
King of Bulgaria among the other titles, demanded that Ivan Sratsimir acknowledge his
suzerainty and become his vassal. When the Bulgarian ruler refused, Louis I marched from Hungary on 1 May 1365 and captured Vidin on 2 June after a brief siege. The rest of the
Vidin Tsardom was conquered in the next three months. Ivan Sratsimir and his family were captured and taken to the castle of Humnik in
Croatia and the region of Vidin was placed under direct Hungarian rule governed through a
Ban appointed by the King of Hungary. That was in fact the first forceful conversion in the country after the
Christianization of Bulgaria five centuries earlier. In a contemporary book, a monk wrote: Initially Ivan Alexander, who was still nominally the rightful ruler of Vidin, did not take active measures for its recovery, although his refusal to give safe conduct to the Byzantine emperor
John V Palaiologos who was returning to
Constantinople from Western Europe was explained by the deterioration of the Bulgarian–Hungarian relations. By 1369, however, he organised an Orthodox anti catholic-Hungarian coalition for the liberation of Vidin with the participation of the Wallachian
voivode Vladislav I Vlaicu and despot
Dobrotitsa. The allied campaign was a success and after it was supported by a popular uprising in Vidin against the Catholic clergy and the Hungarian authority, Louis I had to give up his claims and restore Ivan Sratsimir to the throne in Vidin in the autumn of 1369. According to historian J. Fine, Ivan Sratsimir was allowed to return to Vidin by Louis I as a Hungarian vassal because of his popularity among the population and because Ivan Sratsimir used the Hungarian patronage to assert independence from his father and later to resist his brother in
Tarnovo.
Reign after 1371 after the death of Ivan Alexander. Ivan Sratsimir controlled Vidin to the north-west, his brother Ivan Shishman the central regions and despot
Dobrotitsa controlled the coast to the east. After the death of emperor Ivan Alexander on 17 February 1371, Ivan Sratsimir broke off the last links that connected Tarnovo and Vidin and began to rule without even nominal acknowledgement to the authorities in Tarnovo. The authority of Ivan Sratsimir was treated as equal to that of Ivan Shishman and the details suggest that he was even presented as a senior ruler. Due to the insufficient information, some early Bulgarian historians such as
Konstantin Jireček supported the hypothesis that Ivan Sratsimir and Ivan Shishman were engaged in a military conflict over
Sofia but the idea has been dismissed by most modern historians. In fact, despite the rivalry, the brothers scrupulously maintained relations until 1381 and Ivan Sratsimir was even considered as a potential successor by Ivan Shishman. The relations between the two Bulgarian states worsened in 1381 when Ivan Sratsimir broke the connections with the
Bulgarian Patriarchate in Tarnovo and instead placed the Archbishopric of Vidin under the jurisdiction of the
Ecumenical Patriarchate of Constantinople. That decision was a demonstration of the independence of Vidin from Tarnovo but did not lead to open conflict between the two. The hostility between Ivan Sratsimir and Ivan Shishman remained on the eve of the
Ottoman invasion. Most historians agree that in the 1370s and the early 1380s, Vidin was still away from the route of the Ottoman campaigns and was not endangered. During and after the massive Ottoman invasion in north-eastern Bulgaria in 1388, sources suggest that relations between the two brothers were uneasy. Ivan Sratsimir remained inactive while the Ottomans destroyed the remains of the Tarnovo Tsardom –
Tarnovo fell in 1393 and Ivan Shishman was killed in 1395. The Ottoman garrison of
Oryahovo tried to resist but the local Bulgarians managed to capture it. However, the Christian army suffered a heavy defeat on 25 September in the
battle of Nicopolis and the victorious Ottoman sultan
Bayezid I immediately marched to Vidin and seized it by the end of 1396 or the beginning of 1397. Ivan Sratsimir was captured and imprisoned in the Ottoman capital
Bursa where he was probably strangled. ==Culture, economy and religion==