Trier is a city in Rhineland-Palatinate, southwestern Germany, with a population of 114,914 (2016). It lies on the right bank of the Moselle (Mosel) River, surrounded by the foothills of the Eifel, Hunsrück, and Mosel mountains, just east of the border with Luxembourg.
Centre of Christianity
After it became a bishopric in the 4th century, the town was a centre of Christianity north of the Alps, a status it maintained after its capture by the Franks in the 5th century. Trier was designated an archbishopric in 815, its archbishops becoming temporal princes with power over extensive territory; they were made electors of the Holy Roman Empire in the late 12th century.
Trier was a Roman colony from the 1st century AD and then a great trading centre beginning in the next century. It became one of the capitals of the Tetrarchy at the end of the 3rd century, when it was known as the ‘second Rome’. The number and quality of the surviving monuments are an outstanding testimony to Roman civilization.