Trier lies in a valley between low vine-covered hills of red sandstone in the west of the state of Rhineland-Palatinate, near the border with Luxembourg and within the important Moselle wine region.
The city is the oldest seat of a bishop north of the Alps. In the Middle Ages, the Archbishop of Trier was an important prince of the church, as the Archbishopric of Trier controlled land from the French border to the Rhine. The Archbishop also had great significance as one of the seven electors of the Holy Roman Empire.