Passage: Ivan Alexander (Bulgarian: Иван Александър, transliterated Ivan Aleksandǎr; pronounced [iˈvan alɛkˈsandər]; original spelling: ІѠАНЪ АЛЄѮАНдРЪ), also sometimes Anglicized as John Alexander, ruled as Emperor (Tsar) of Bulgaria from 1331 to 1371, during the Second Bulgarian Empire. The date of his birth is unknown. He died on 17 February 1371. The long reign of Ivan Alexander is considered a transitional period in Bulgarian medieval history. Ivan Alexander began his rule by dealing with internal problems and external threats from Bulgaria's neighbours, the Byzantine Empire and Serbia, as well as leading his empire into a period of economic recovery and cultural and religious renaissance.However, the emperor was later unable to cope with the mounting incursions of Ottoman forces, Hungarian invasions from the northwest and the Black Death. In an ill-fated attempt to combat these problems, he divided the country between his two sons, thus forcing it to face the imminent Ottoman conquest weakened and divided.

Question: When did Ivan Alexander's reign in Bulgaria first begin?
1331