Task: Question Generation
Input (English): Passage: The medieval Bulgarian state was restored as the Second Bulgarian Empire after a successful uprising of two nobles from Tarnovo, Asen and Peter, in 1185, and existed until it was conquered during the Ottoman invasion of the Balkans in the late 14th century, with the date of its subjugation usually given as 1396, although some fringe views place it at 1422. Under Ivan Asen II in the first half of the 13th century the country gradually recovered much of its former power, though this did not last long due to internal problems and foreign invasions. The Empire became tributary to the Golden Horde, a successor state of the Mongol Empire in the 13th to 14th centuries. After the death of Emperor Ivan Alexander in 1371 Bulgaria was split into three countries and in the following decades fell under the domination of the Ottomans.
Output (English): Who was the leader before Ivan Alexander?