It is of this Benedictine monastery and nunnery that the present ruins are the remains, and they were formerly connected by a causeway which extended from the nunnery to the monastery. After a struggle, the Culdees seem to have conformed to the new order of Benedictines, and the head of the Culdees was represented by the Prior of Iona, whom we afterwards find in the monastery. Iona was suffragan to the Bishop of Man and the Isles till 1431, when the Abbot of Iona made obedience to the Bishop of Dunkeld. In 1498, the Isles were made suffragan to St. Andrews; in 1506 they passed back to the care of the Bishop of the Isles; and from that date till the Reformation the abbey church became the cathedral church of the diocese. In 1648 Charles I. granted the island to Archibald, Marquis of Argyll,[196] and it still belongs to his descendant, the Duke of Argyll. The diocese contained forty-four parishes. Surrounding the Chapel of St. Oran is a very ancient churchyard, containing beautiful specimens of Highland carved tombstones, and near which reposes the dust of Scotch, Irish, and Norwegian kings and ecclesiastics. The late Duke of Argyll both preserved and restored, and the foundations of the chapels and cloisters have been plainly marked out, and give a clear idea of the original plan of the abbey. The abbey or cathedral, although begun in the twelfth century, took a long time in building, was altered and added to, and is classed with the buildings of the Third Pointed period, as the greater part of the work connected with it belongs to a late date.[197] It is cruciform in shape, consisting of nave, transepts, and choir, with sacristy on the north side of the choir, and aisle on the south. Near the west entrance was a small chamber called St. Columba's tomb. Over the crossing is a square tower, 70 feet high, and supported by arches resting on four pillars. It is lighted on one side by a window formed by a slab with quatrefoil openings, and on the other by a marigold or Catherine-wheel window with spiral mullions. The capitals of the pillars are carved with beautiful ornamentation and grotesque figures, which are still sharp and well defined.[198] There are three sedilia, and the high altar seems to have been of marble. North of the nave is the cloister-garth; to the north and east of the cloisters are the refectory and chapter-house; the building over the chapter-house was the library, which was large and valuable. There were said to be many crosses in Iona; the entire ones are St. Martin's Cross, opposite the west door of the abbey church, and Maclean's Cross, on the wayside between the nunnery and the cathedral. There are the ruins of a small detached chapel to the north-east of the chapter-house, and of another to the west of the cloister: to the north-east of the cloister lie the total ruins of what is called the abbot's house.[199] A short distance north-east of the abbey church, at