sentences:  Sens Cathedral was soon was soon followed by Senlis Cathedral (begun 1160), and the most prominent of all, Notre-Dame Cathedral in Paris (begun 1160).Their builders abandoned the traditional plans and introduced the new Gothic elements.The builders of Notre Dame went further by introducing the flying buttress, heavy columns of support outside the walls connected by arches to the walls, which received and counterbalanced the thrust from the rib vaults of the roof.