There are numerous castles in Gloucestershire, a county in South West England. They consist of motte-and-baileys, fortified manor houses, ringwork, and ring-mottes. A motte-and-bailey castle has two elements, the motte is an artificial conical mound with a wooden stockade and stronghold on top, usually a stone keep or tower. A bailey is a defended enclosure below the motte, surrounded by a ditch. Motte-and-bailey castles were the most common type of castle in England following the Norman Conquest. Ringworks are similar to motte-and-baileys although lack the characteristic motte; across England they are an uncommon form of fortification but were popular in the west of Gloucestershire in the 11th century. A ring-motte is a ring-work with a raised centre. A shell keep was a motte with a stone