Thionville (; ; ) is a city in the northeastern French department of Moselle. The city is located on the left bank of the river Moselle, opposite its suburb Yutz. History Thionville was settled as early as the time of the Merovingians. After the fall of the Western Roman Empire, the region was inhabited by the Germanic Alamanni. It was known in the Latin of that era as Theudonevilla or Totonisvilla. King Pepin the Short had a royal palace constructed here. The Synod of Thionville was held here beginning on February 2, 835. It reinstated Emperor Louis the Pious and reversed his former conviction on crimes — none of which he actually committed — and deposed the Archbishop of Rheims, Ebbo. The Synod was composed of 43 bishops. On February 28, 835, in Mainz, Ebbo admitted that Louis had not committed the crimes of which he had been indicted and for which he had been deposed as Holy Roman Emperor. From the 10th century onward, the area was part of the Holy Roman Empire. It was in possession of the House of Luxembourg until 1462 and then, until 1477, of the Duke of Burgundy. From 1477 to 1643, it was Habsburg territory. Eskil, Archbishop of Lund, was imprisoned at Diedenhofen (at the instigation of the Archbishop of Bremen?) upon his return from his 1153 pilgrimage to Rome. The Siege of Thionville in June 1639 occurred as part of the Thirty Years' War. In 1659 Diedenhofen was annexed by France. Fortifications were constructed under the direction of Sébastien de Vauban. In 1792, Thionville was besieged by the Duke of Brunswick, who unsuccessfully sought to defeat the French Revolution and restore Louis XVI to the royal throne. The writer François-René de Chateaubriand was left for dead during Condé's military émigré expedition against Thionville in 1792. After the Franco-Prussian War of 1870, the area of Alsace-Lorraine was annexed by the newly created German Empire in 1871 by the Treaty of Frankfurt and became a Reichsland. Thionville once again became Diedenhofen and became a prosperous city. Some large neo-Romanesque buildings typical of the German Empire were constructed in the city. The German Army decided to build a fortress line from Mulhouse to Luxembourg to protect the new Reichsland. The centerpiece of this line was the great Moselstellung, a fortress system protecting Metz and Diedenhofen. The fortifications around Diedenhofen centered on three main forts: the