sentences:  Since Ivan Shishman was the first son born to Ivan Alexander after his accession to the throne ("born in the purple"), Theodora insisted that he was the only one worthy of the crown.Ivan Shishman was crowned co-emperor by his father who made his elder son Despot of Vidin in exchange.After Ivan Alexander died in 1371, Ivan Shishman became Tsar and Ivan Sratsimir declared Vidin a separate empire.