294 COMPARATIVE ARCHITECTURK. and carrying the weight lower down the wall, which they also help to steady. (5.) Aisle Roofs in the early period were merely a continua- tion of the rafters of the nave. At North Walsham, Norfolk (a tie-beam roof), the tie-beam of the aisle is carried through the wall, forming a corbel for the wall-piece of the nave roof, thus binding the whole together. Aisle roofs were usually simple, intermediate trusses being introduced to strengthen the purlins. When they were gabled they were usually of low pitch, and the hammer-beam was rarely introduced for these. New Walsingham Church (No. 113 g) and Ixworth Church (No. 113 f) are good types of aisle roofs. 3. EXAMPLES. The student is referred to Gothic Architecture in Europe (page 273) for the different types of buildings erected during the Middle Ages which are here further enlarged upon. As mentioned in architectural character (page 283), these buildings were mostly erected in the styles known as Norman, Early English, Decorated, and Perpendicular. CATHEDRALS. Refer to the General Introduction to Gothic Architecture (page 273). The constitution and foundation of English Cathedrals is important and is largely responsible for their monastic character and general arrangement. They may be divided into three classes :■ — (a.) Cathedrals of the Old Foundation. {b.) Cathedrals of the Monastic Foundation. (c.) Cathedrals of the New Foundation. (a.) The Cathedrals of the old foundation are those which, being served by secular clergy, were not affected by the reforms of Henry VHI. The following is a list : — The Cathedrals of York, Lichfield, Wells, Exeter, Salisbury, Chichester, Lincoln, Hereford, S. Paul, London, and the Welsh Cathedrals of Llandaff, Bangor, S. David's, and S. Asaph. (h.) The Cathedrals of the monastic foundation are those which were originally served by rcgiilav clergy or monks, and which were reconstituted at the dissolution of the monasteries as chapters of secular canons. The following is a list : — The Cathedrals of Canterbury, Durham, Rochester, Winchester, Worcester, Nor- wich, Ely, Carlisle, Peterborough, Gloucester, Chester, Oxford, and Bristol. Westminster Abbey was a Cathedral Church from A.D. 1540-1545. When the chang-e in these monastic establishments was
