Otto III, Holy Roman Emperor

Otto III was Holy Roman Emperor and King of Italy from 996 until his death in 1002, the only son of Emperor Otto II and Theophanu. Crowned King of Germany in 983 at age three, he ruled through a series of regents, first his mother Theophanu and then his grandmother Adelaide of Italy, before marching to Italy in 996 to claim the imperial title and suppress a Roman revolt led by Crescentius II. He installed his cousin as Pope Gregory V, the first German pope, and later Sylvester II, strengthening imperial control over the church, while also extending Christian influence into Poland and Hungary, including the crowning of Stephen I as Hungary's first Christian king. He died of a sudden fever in 1002 at age 21 with no clear heir, plunging the empire into crisis.