The Electorate of Trier (German: Kurfürstentum Trier or Kurtrier) was an ecclesiastical principality of the Holy Roman Empire that existed from the end of the 9th to the early 19th century. Temporal possessions were ruled by the Archbishop in his function as prince-elector of the empire. The Alte Burg ("old castle") is a former Electoral castle. It is a four-winged complex (with an extended north wing) with two round towers, and a keep, built ca. 1312, altered in 1499 after fire and in the 17th century. On the east wing and on the former tollhouse there are coats of arms of Archbishops Karl Kaspar von der Leyen-Hohengeroldseck (1652-1672) and Johann VIII Hugo von Orsbeck (1672-1711).