§ 31. There can be no doubt that, in the earlier part of the middle ages, while the high pitched roof prevailed in the main body of the building, the spire was considered the proper termination of a tower. Its chief development naturally took place in districts where good roofing stone was plentiful; and the finest English spires, with a few exceptions, are to be found in south Lincolnshire, Northamptonshire, Leicestershire, and Rutland. In less favoured districts, timber spires, covered with lead or shingles, were placed upon towers. Many of these remain in Surrey and Sussex. The spire may be regarded as the natural development of the conical roofs with which the towers of the eleventh and early twelfth centuries were usually crowned--an invaluable, if exceptional, example of which remains at Sompting, near Worthing. These must generally have been of wood with leaden coverings. The earliest general development of the stone spire is probably to be traced to south Lincolnshire, where the low broach spires of Sleaford, Rauceby, Frampton, and a few other churches, appear to belong to the last years of the twelfth, or earliest years of the thirteenth century. The spire continued to be fashionable in this and the neighbouring districts, long after it had become unusual in other parts of England. Grantham spire exercised an enduring influence upon its neighbourhood. It was the model upon which the builders of the spire of Oakham endeavoured to improve, with less striving after height and more coherence of design. From Oakham was closely derived the tower of Exton in Rutland, where the builders raised their spire upon an octagonal base. The octagon at Exton was probably the parent of those octagons which, rising on the summit of towers, reach their climax in the lantern at Boston, and in the octagonal frame which surrounds the lower part of the spire at Patrington. Other details at Exton bore fruit in the spires of Oundle and Kettering. At the very end of the middle ages, the feeling for the spire in Lincolnshire was still so strong that the tower of Louth was designed for a spire in the middle of the fifteenth century, and the spire itself was brought to completion in 1515.