The Holy Roman Emperors were rulers of the Holy Roman Empire, a multi-ethnic complex of territories in central Europe that existed from the early Middle Ages until 1806. The title was often held by kings of the German states, and the emperors were seen as the secular leaders of Christendom, with a role in both political and religious matters. The election of a Holy Roman Emperor was typically conducted by a group of prince-electors, and the position was not hereditary. Notable emperors include Charlemagne, who was crowned in 800 AD, and Frederick Barbarossa, who reigned in the 12th century. The empire's influence waned over time, leading to its eventual dissolution.