After the period of invasions, the town prospered in the Middle
Ages due, in part to the growing political influence of its bishops. The diocese covered
Champagne, the Duchy of Burgundy and Franche-Comté, and the bishops gained the right to
coin money in the 9th century and to name the military governor of the city in 927.
The Bishop of Langres was a duke and peer of France.
The troubled 14th and 15th centuries were reason enough for the town to strengthen its
fortifications, which still give the old part of the city its fortified character. The
Renaissance, which returned prosperity to the town, saw the construction of numerous
civil, religious and military buildings that still stand today. In the 19th century, a
"Vauban" citadel was added.
Today Langres is a unique historical town with numerous art treasures within the ancient
defensive walls surrounding the old city, including twelve towers and seven gates.
The cathedral of Saint-Mammès is a late 12th-century structure dedicated to Mammès of
Caesarea, a third-century martyr.