After the fall of the Roman empire, few buildings large enough to require much in the way of vaulting were built for several centuries. In the early Romanesque period, a return to stone barrel vaults was seen for the first great cathedrals; their interiors were fairly dark, due to thick, heavy walls needed to support the vault. One of the largest and most famous churches enclosed from above by a vast barrel vault was the church of Cluny Abbey, built between the 11th and 12th centuries.