Bishop Joceline, previously abbot of Melrose, was consecrated in 1175. Under him, and by his influence, the burgh received many privileges, and advanced in prosperity. Between 1189 and 1192 he was engaged in restoring or adding to the building.

The original church of Bishop John, “built, perhaps, chiefly of wood,” had been recently destroyed by fire. Through the exertions of Bishop Joceline a society was founded to collect funds for its restoration, and the work was sufficiently advanced for consecration on 6th July 1197.[60]

It was generally believed, at one time, that the existing choir and lower church were erected by Bishop Joceline; but it has been shown by Mr. John Honeyman, architect, in various papers on the subject, published at various times during the last forty years, that only a small part of the structure which now exists may possibly be of the time of that bishop.

According to Mr. Honeyman, a portion of the lower church, situated at its south-west angle, and extending from the transept eastwards to the third buttress of the choir, and including one bay and a half, shows some differences in its style of architecture from the remainder, and may be regarded as of the transition style, and may thus be of the date of Bishop Joceline; while the remainder of the lower church and the whole of the choir are built in the first pointed style, and cannot be earlier than the second quarter of the thirteenth century. The actual builder of the lower church and the choir above, as they now exist, was Bishop William de Bondington (1233-1258). A large part of the structure was completed before his death in the latter year, and the style of the work thoroughly corresponds with his period. In 1242 an ordinance was made for a national collection annually during Lent in aid of the building.[61]

According to Mr. Honeyman, the foundations of the nave were laid, and part of the walls was carried up, before the building of the choir was begun.

Most of the nave appears, from the style of its architecture, to have been chiefly erected at the end of the thirteenth or the beginning of the fourteenth century, but there is no record of its construction. It forms one of the finest examples of the late first pointed or early decorated style in Scotland.

Bishop Wishart occupied the see during the greater part of the War of Independence, and supported the Scottish party on all occasions. He obtained permission from Edward I. to cut timber in the forest of Luss for the purpose of erecting the spire of the cathedral; and it was one of the causes of accusation against him which led to his imprisonment in England that he had used the timber so obtained, not for building the spire, but for making engines of war with which to attack Edward’s forces.

The wooden spire of the cathedral, which was erected during the fourteenth century, was struck by lightning and destroyed in 1400. A new tower of masonry was erected over the crossing by Bishop Lauder (1408-25), who carried the work as high as the main parapet. This bishop appears also to have begun the completion of the chapter house, a detached structure lying to the north-east of the choir. The walls of this building were partly erected about the time of the construction of the choir, but were afterwards raised to two stories in height and vaulted by Bishop Cameron.

Bishop Lauder was succeeded, in 1425, by Bishop Cameron, called “The Magnificent,” from his lavish expenditure and the splendour of his Court. He erected the stone spire above the tower of Bishop Lauder, and also completed the chapter house wing containing the sacristy on the upper floor and the chapter house on the ground floor. His arms are still to be seen on the portions of the structure erected by him. The beautiful rood screen was also probably constructed by him.

During Bishop Cameron’s reign the episcopal see was at the highest point of its power and splendour. The prebendaries, who were originally seven in number, were now increased to thirty-two, and the bishop required that they should all have manses,[62] and reside near the cathedral. The Episcopal Court thus became of great extent and importance, and was said to rival that of the king. Bishop Cameron died in 1446. He was succeeded by Bishop William Turnbull, the founder of Glasgow University. His arms appear on the upper part of the chapter house wing.