The number of churches founded or rebuilt soon after the Norman Conquest must have been enormous, for in examining churches of every date and in every part of England it is common to find some fragment of Norman work remaining from a former church: this is very frequently a doorway left standing or built into walls of later date: and, in addition to these fragments, no small number of churches, and more than one cathedral, together with numerous castles, remain in whole or in part as they were erected by the original builders. Norman architecture is considered to have prevailed in England for more than a century; that is to say, from the Conquest (1066) to the accession of Richard I. (1189). For some details of the marks by which Norman work can be recognised the reader is referred to the companion volume;[36] we propose here to give an account of the broader characteristics of the buildings erected during the prevalence of the style. * * * * * The oldest remaining parts of Canterbury Cathedral are specimens of Norman architecture executed in England immediately after the Conquest. This great church was rebuilt by Archbishop Lanfranc (whose episcopate lasted from 1070 to 1089), and in extent as laid out by him was very nearly identical with the existing structure; almost every portion has, however, been rebuilt, so that of his work only the towers forming transepts to the choir, and some other fragments, now remain. More complete and equally ancient is the chapel in the Tower of London, which consists of a small apsidal church with nave and aisles, vaulted throughout, and in excellent preservation. This building, though very charming, is almost destitute of ornament. A little more ornate, and still a good example of early Norman, is St. Peter's Church, Northampton (Fig. 172), the interior of which we illustrate. To these examples of early Norman we may add a large part of Rochester Cathedral, and the transepts of Winchester. The transepts of Exeter present a specimen of rather more advanced Norman work; and in the cathedrals of Peterborough and Durham the style can be seen at its best. [Illustration: FIG. 172.--NORMAN ARCHES IN ST. PETER'S CHURCH, NORTHAMPTON.]