Trier (/trɪər/ TREER, German: [tʁiːɐ̯] ; Luxembourgish: Tréier [ˈtʀɜɪ̯ɐ] ), formerly and traditionally known in English as Trèves (/trɛv/ TREV, French: [tʁɛv] ) and Triers (see also names in other languages), is a city on the banks of the Moselle in Germany. It 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.
Founded by the Romans in the late 1st century BC as Augusta Treverorum ("The City of Augustus among the Treveri"), Trier is considered Germany's oldest city. It is also the oldest seat of a bishop north of the Alps. Trier was one of the four capitals of the Roman Empire during the Tetrarchy period in the late 3rd and early 4th centuries. In the Middle Ages, the archbishop-elector of Trier was an important prince of the Church who controlled land from the French border to the Rhine. The archbishop-elector of Trier also had great significance as one of the seven electors of the Holy Roman Empire. Because of its significance during the Roman and Holy Roman empires, several monuments and cathedrals within Trier are listed as a UNESCO World Heritage Site.