Earthwork castles fall into two main types, mottes and ringworks. The former are usually associated with one or more baileys or courtyards, whilst a ringwork generally stands in isolation. The term "enclosure" is preferred by some with regard to ringworks, but "ringwork" is now an accepted term for this type of castle.

A motte is an enditched mound, usually artificial, which supported the strongpoint of the motte-and-bailey castle, overshadowing the bailey or enclosed courtyard below. It is predominantly rounded in plan, but square or rectangular mottes are known, especially in Scotland. The height of mottes varies greatly, the majority being under 5m, although a few of the sites built in the years immediately following the Norman Conquest are well known for having some of the largest castle mounds in the country.

A bailey could vary in both shape and size, and a castle could have more than one. There are, however, some mottes which never seem to have had an attached courtyard. We cannot be certain why this should be, but some mottes may have been built as fortified observation posts rather than for permanent occupation. Another reason might be that a motte without a bailey represents an unfinished castle.

The advantage of a motte is obvious, towering as it did in most cases above the surrounding terrain. That it was the key in the defences of this type of castle is emphasized in two contemporary accounts of attacks on two sites in Wales. In 1075, two years after Rhuddlan Castle, Flintshire had been built the bailey was stormed and burnt by Gruffydd ap Cynan. Many Norman soldiers fell in the engagement, and only a few were able to reach the safety of the "tower," a reference to the motte with a timber structure on its summit. The second reference is to Llandovery Castle, Carmarthenshire, in 1116. Although the Welsh were successful in attacking and burning the "outer castle" or bailey, the Normans on the motte caused enough casualties among the assailants for the attack to be withdrawn. It is hardly surprising, therefore, that many of these type of castle were built.

Right: the large motte & stone shell keep at Wiston Castle

Ringworks could vary in form, but were generally circular earthworks, each consisting of a bank and ditch, or they might be D-shaped where a natural scarp formed part of the defences, as it did at Kidwelly Castle, Carmarthenshire. A simple definition might be that a ringwork is a motte-and-bailey without the motte, and as its rampart could enclose a large area, these castles did not always have an additional bailey.

In general, a ringwork must have been quicker and cheaper to throw up than a motte-and-bailey, and this factor undoubtedly accounts for such defences being built when some castles were first constructed in England and Wales. In these cases where the Normans utilized earlier fortifications, such as Roman defences and Anglo-Saxon burhs or defended towns, in the immediate post-conquest period, ringworks seem to have predominated. It cannot be a coincidence that when the Normans were endeavoring to extend their hold on south Wales in the early 12th century, many of the castles were ringworks. Coity, Ogmore and Loughor in Glamorgan, Kidwelly, Llansteffan and probably Laugharne in Carmarthenshire are all good examples of this use of ringwork construction. Here the Normans, during their advance and occupation, were deliberately constructing what they considered to be a quick and effective form of castle.

Medieval Fortifications, John R. Kenyon, Leicester University Press, Leicester and London, 1990.