Specific locations (where known) are given as Landranger map grid reference, usually 8 figure but occasionally 6 or even 4 figure. In the downloadable database I also give the older 12 figure OS map grid reference since making distribution maps from these figures should be straight forward. The accuracy of the OS grid reference given in my sources and by me is variable, at it's best it is accurate to 10m, typographical errors aside it should, at its worst, be accurate to a kilometer. I have tried to check all references against the Ordnance Survey map (current and 1st edition versions)
All map references tend to have a degree of error that occurs because of
a failure to appreciate that a map reference defines a square area and not
a point location. Map references should identify the south eastern corner
of the square area in which a monument is in, the number of digits in the map
reference implying the size of this area; i.e. SO53289999 is a 10m square area.
However, reports often describe a monument as centred on a particular
grid reference. As portable GPS systems become more available grid references
are given with greater numbers of digits, these are not more accurate; defining
a motte sized monument to a 1 sq meter (or even 10 sq cm) area is simply ridiculous.
However, in practice, most 6 or 8 figure map references in this gazetteer should
be considered as point locations, whilst 4 figure references refer to the square
in which a site probably existed.
General location is given by the historic county (Strictly speaking the county as on the 1st edition OS map of the mid to late 19th century), by the current (2005) local authority and by the county after the changes of 1974. Despite some common beliefs the counties of England have never been static and changes of a slight nature where boundaries were tidied up have occurred fairly often. Some major changes took place in 1888 and the historic counties are not the same as the counties in 1973, often given in older sources. Significant differences are;
A major change of administrative areas took place in 1974 and again in 1996. Some sources will refer to administrative areas which were in existence between these dates. The Sites and Monuments records and the authorities with responsibility for recording and protecting historic sites are generally, at a local level, based on the new post 1996 administrative areas in England.
The smallest area of civil authority in England is the Civil Parish, this is used to locate sites is some sources. Modern administrative areas are also not entirely tidy and some non parish areas exist. It should be noted that the Civil Parishes do occasionally change names and boundaries so the Civil Parish given in older sources may not be the same as that given by me. Civil Parishes are not the same as church parishes although they do often cover the same or similar areas and have the same or similar names. They are certainly not the same as medieval manors and any similarity in name must be treated with circumspection.
The medieval administrative areas of Wales were cantrefs and commotes. (Click on the map for a map of the commotes) The so called historic counties were formed by statue in 1535, although some of the counties had existed since the 13th century. In Wales the Sites and Monuments records cover areas that are based on the 1974 administrative areas (Still having some legal status and technically called the Preserved Counties). It should be noted that the pre 1974 and post 1996 counties of Denbighshire and Flintshire are significantly different.
Monmouthshire has had a peculiar status, always closely connected to Wales, it was technically, for a long period, an English county. It is now officially part of Wales but some very old sources might still refer to it as part of England.
The smallest area of civil authority in Wales is the Community, this is used to locate sites is some sources. It should be noted that Communities do occasionally change names and boundaries so the name given in older sources may not the same as that given by me. Communities in Wales are not the same as church parishes although they do occasional cover the same or similar areas and have the same or similar names.
Genuki does give some information on the various boundary change.
In general broad sweeping statements about castle locations should be treated with caution as regional variation can be very significant. With this warning in mind I do make the following comments.
I am of the opinion that in England and, to a slightly lesser extent, in Wales the most important factor concerning the location of a castle is the prior social status of the site. Several Norman castles have now been shown to be built on earlier saxon high status sites and I am convinced that very many Norman castles were extensive rebuilding of Saxon thegn's bughs or Welsh Llys. The most obvious sign of this association is the close relationship with the parish church and with settlement. See the essay Dominion in the Landscape by Lucy Marten-Holden for the clear evidence of this in Suffolk. Her thinking can be more widely expounded in England and probably also in Wales although in the Welsh marches, Wales and the north of England warfare was more active, extensive and frequent than in the rest of England and military considerations in the siteing of castles does become a more important factor. An example would be Richmondshire in North Yorkshire where the major Saxon thegnal site of Gilling may have initially been used as the the site of Count Alan's castle but he soon moved to a military stronger site at Richmond, possibly in response to the major uprising which ultimately lead to the vast devastation of the 'Harrying of the North'.
The placing of fortifications for military strength on hilltops, appears to be a rare occurrence in England and fairly uncommon in Wales although it does occur, particularly in areas of frequent warfare (Basically the Welsh Marches.). I would also suggest that the native welsh may have had a greater feeling for the Iron Age hillforts built by their ancestors and were more ready to reuse these structures than the Normans or English for whom these structures generally had no particular historical significance.
William the Conquer placed castles in all the county towns of England, most of these continued to function as major administrative centres throughout the medieval period. However, the castle at Derby went out of use quickly, since Derbyshire was generally administered closely with Nottinghamshire and the major castle of Nottingham thus superceded the small castle at Derby. A similar story is true for the small royal castle of Stafford, although this seems to have had a slightly longer service, before its function was taken over by Shrewsbury.
Mary Higham makes a strong case for suggesting that some mottes in Lancashire were sited at river crossing. I believe there is evidence to suggest this may be more widely true. Higham suggests medieval rivers, untamed by modern drainage and management represented a considerable barrier to passage, particularly for those on horseback or with (stolen) livestock and that control of crossing points was an early way of ensuring control until more centralised county control was established. I would like to suggest that there may have been a strategic plan by William I to control all of the crossings of the Trent, fore instance. There is also a suggestion that in Wales some castles were sited to act as taxation points. It should be remembered that in most of medieval Wales wealth was based on cattle and this wealth was realised by selling these cattle for meat, mainly in England. Therefore, herds of cattle were moving around Wales and, whilst a band of robbers might slip past a castle, a herd of cattle can not. Therefore, castles sited on roads with some restrictive passage, such as a narrow pass, could both collect taxes and duties and prevent the stealing of cattle. (Much Welsh warfare may well have just been cattle raids and the concerns regarding this 'warfare' were more about civil matters regarding taxation and theft rather than military matters regarding the political authorities.).
Robert
Liddiard makes interesting comments about the economic and social costs of
castles and suggests that there was some pressure to not site castles in good
agricultural areas, at least in East Anglia (Liddiard, 2000, ‘Population
Density and Castle-Building: Some Evidence from East Anglia’, Landscape
History, 22 pp.37-46). However, in the welsh and northern marches farmhouse
seem to have been fortified and some small mottes in the welsh marches could
really be considered to be 11th and 12th century earthwork 'pele' towers since
these were of similar social status and function to the 13th-15th pele towers
of the Northern Marches (King and Spurgeon).
[This shows the difficulty associated with defining the term castle where a
large motte and bailey of a major lord, such as Clun,
is classed with a small isolated motte of a minor knight such as Rorrington].
Arguments about the military significance of the location of castles are complex. The latest work on this is Stuart Prior's A Few Well-Positioned Castle: The Norman Art of War (Tempus, 2006). There are difficulties with the case he put. Firstly a number of his Norman castles have Saxon origins which suggests it is the Saxon's who were placing Thegnal burhs for military reasons rather than the Normans. Secondly a river crossing of a major road is a military 'nodal point' but it is also a sensible place to site a political or economic centre. A castle at a river crossing is not per se military. The big difficulty is that castles are not a homogenous group. There are over a hundred castles in Shropshire, but only ten or so of these are large enough to house a military garrison so most castles are not military. However, these ten or so castles are the castles with extensive documented histories, because of the medieval and modern fascination with warfare and their relative importance as political centres. So a few atypical castle dominate the historic and modern record and vastly distort the picture of castles as a whole. Other issues arise from the not always clear boundaries between military and civil authority (This is not always clear in the modern world and was distinctly blurry in the medieval world.) Is a castle the centre of a military authority or of a civil authority personified in an individual who had some military duties and responsibilities? I would argue that in almost all cases it is the latter case.