Sens () is a commune in the Yonne department in Bourgogne-Franche-Comté in north-central France, 120 km from Paris. Sens is a sub-prefecture and the second city of the department, the sixth in the region. It is crossed by the Yonne and the Vanne, which empties into the Yonne here. History The city is said to have been one of the oppida of the Senones, one of the oldest Celtic tribes living in Gaul. It is mentioned as Agedincum by Julius Caesar several times in his Commentarii de Bello Gallico. The Roman city was built during the first century BC and surrounded by walls during the third (notable parts of the walls still remain, with alterations along the centuries). It still retains today the skeleton of its Roman street plan. The site was referred to by Ammianus Marcellinus as Senones (oppidum Senonas), where the future emperor Julian faced an Alamannic siege for a few months, but it did not become an administrative center until after the reorganization of the Roman Empire in 375, when it was the chief town of Lugdunensis Quarta. During the Middle Ages its archbishops held the prestigious role of primate of Gaul and Germany. The bishop of Sens became an archbishop as early as the mid-5th century, but the cult of the traditional founders Savinian and Potentian, not mentioned by Gregory of Tours, did not appear until the 8th century, when they were added to the local recension of the Seventy Apostles. The Hôtel de Sens in Paris was their official residence in that city. The Archdiocese of Sens ruled over the dioceses of Chartres, Auxerre, Meaux, Paris, Orléans, Nevers and Troyes, summarized by the acronym CAMPONT. This city was conquered by a Muslim army in 725 AD, but was abandoned quickly after the death of the commander of the army, Anbasa ibn Suhaym al-Kalbi, from natural causes. Starting from 1135, the cathedral of Sens, dedicated to Saint Stephen, was rebuilt as one of the first Gothic cathedrals. There, in 1234, Louis IX of France celebrated his wedding to Marguerite of Provence. Sens witnessed the trial of Peter Abelard. Pope Alexander III sojourned for some time in the city, and Thomas Becket spent part of his exile between 1162 and 1165. The Archdiocese of Sens hosted a number of church councils and the first Archbishop of Uppsala was consecrated there. William of Sens was the principal architect