Trier, formerly known in English as Treves, is a city in Germany on the banks of the Moselle. 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. Founded by the Celts presumably in the late 4th century BC as Treuorum, it was later conquered by the Romans in the late 1st century BC and renamed Trevorum or Augusta Treverorum (Latin for "The City of Augustus among the Treveri"), Trier may be the oldest city in Germany. It is also 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.
With an approximate population of 105,000, Trier is the 4th-largest city in its state, trailing Mainz, Ludwigshafen, and Koblenz.[4] The nearest major cities are Luxembourg (50 km or 31 mi to the southwest), Saarbrücken (80 kilometres or 50 miles southeast), and Koblenz (100 km or 62 mi northeast).
Trier is home to the University of Trier, the administration of the Trier-Saarburg district and the seat of the ADD (Aufsichts- und Dienstleistungsdirektion), which until 1999 was the borough authority of Trier, and the Academy of European Law (ERA). It is one of the five "central places" of the state of Rhineland-Palatinate. Along with Luxembourg, Metz and Saarbrücken, fellow constituent members of the QuattroPole union of cities, it also forms a central place of the greater region encompassing Saar-Lor-Lux (Saarland, Lorraine and Luxembourg), Rhineland-Palatinate, and Wallonia.