William of Sens

William of Sens or Guillaume de Sens (died 11 August 1180) was a 12th-century French master mason and architect, believed to have been born at Sens, France. He is known for rebuilding the choir of Canterbury Cathedral between 1174 and 1177, counted as the first important example of the Early Gothic Style of architecture in England, finished in 1184. Before Canterbury, he worked on Sens Cathedral. According to one English source, he died at Canterbury on 11 August 1180. According to other sources, he died in France, after returning from England.

Sens Cathedral and Canterbury Cathedral Very little is known of the early life of William of Sens. It is believed that he learned the skills of cathedral construction working on Sens Cathedral, the first complete Gothic cathedral in France, built between 1135 and 1148, shortly before Notre-Dame de Paris. William is believed to have known other early Gothic buildings at Notre-Dame de Paris, Soissons, Rheims, Cambrai, Arras, and at Notre-Dame la Grande, Valenciennes (begun 1171, destroyed in the French Revolution).

William is responsible for the choir eastwards of the crossing and for the western transept. in the choir, and devised the structure which made the walls between the structural elements thinner, allowing more and larger windows which filled the church with light.

The innovations of William at Canterbury included the motif of pale Caen stone contrasted with dark column shafts of Purbeck marble, and the sexpartite rib-vaults, which form paired bays in the nave. The work on Canterbury Cathedral was completed by another architect, known only as William the Englishman, who followed his plans. The second William completed the eastern portion of the church, including the vaults of the choir, the eastern transept, the Trinity Chapel, and chapel of Thomas Becket. It was finished in 1184, not long after William of Sens's death.