Increasing military and cultural contacts with the Muslim world, including the Norman conquest of Islamic Sicily between 1060 and 1090, the Crusades, beginning 1096, and the Islamic presence in Spain, may have influenced mediaeval Europe's adoption of the pointed arch, although this hypothesis remains controversial. The structural advantages of pointed arches seems first to have been realised in a medieval Latin Christian context at the abbey church known as "Cluny III" at Cluny Abbey. Begun by abbot Hugh of Cluny in 1089, the great Romanesque church of "Cluny III" was the largest church in the west when completed in 1130"." Kenneth John Conant, who excavated the site of the church's ruins, argued that the architectural innovations of "Cluny III" were inspired by the Islamic architecture of Sicily via Monte Cassino. The Abbey of Monte Cassino was the foundational community of the Benedictine Order and lay within the Norman Kingdom of Sicily, . The rib vault with pointed arches was used at Lessay Abbey in Normandy in 1098, and at Durham Cathedral in England at about the same time. In those parts of the Western Mediterranean subject to Islamic control or influence, rich regional variants arose, fusing Romanesque, Byzantine and later Gothic traditions with Islamic decorative forms, as seen, for example, in Monreale and Cefalù Cathedrals, the Alcázar of Seville, and Teruel Cathedral.