Celestine, the abbot of this monastery, appears to have attempted to thrust out the prior Celtic community; but the latter, with the support of the clergy of the north of Ireland, resisted and vindicated their right to remain in the monastery. The Celtic community, however, appear to have ultimately adopted the Benedictine rule, “while the functionary formerly known as the Head of the Culdees was represented by the prior of Iona, whom we afterwards find in the monastery.” About 1200 the districts to the west of the great range of Drumalban, which formerly belonged to the diocese of Dunkeld, were separated from it and formed into a new bishopric, first called of Argyle and afterwards of Lismore. During the fourteenth and fifteenth centuries Iona was under the Bishop of Dunkeld, but in 1507 John, Bishop of the Isles, obtained the annexation of Iona to his see, and the Abbey Church became the cathedral of the diocese, and so continued till the Reformation. In 1561 the abbey suffered from the Act anent “demolishing all the abbeys of monks and friars, and for suppressing whatsoever monuments of idolatrie were remaining in the realm.” The carrying out of this Act was remitted to Argyll and Glencairn, and much has been written with regard to the great damage caused by the mob to the buildings and monuments and the valuable library. The island passed into the hands of M‘Lean of Duart, but from 1567 onwards the Protestant bishops of the Isles seem to have had the abbey in their possession. The buildings, however, appear to have been neglected, and Charles I., in 1635, directed £400 to be spent in repairing them. But that does not appear to have been done, and by the end of the seventeenth century the edifices had fallen into ruin. In 1693 the island came into the hands of the House of Argyll, and within recent years the ancient buildings have been put in a good state of preservation by the present Duke. The edifices which still survive in the island, although ruinous, exhibit probably the completest and most interesting group of ancient ecclesiastical structures in Scotland. There is first the Chapel of St. Oran, a small twelfth century structure, surrounded by the very ancient churchyard, which contains so many beautiful specimens of Highland carved tombstones,[33] admirably illustrated by the late James Drummond, R.S.A., in his work on Highland monuments. Then there are the remains of the Benedictine Monastery, and those of the Benedictine Nunnery, at a short distance on each side of St. Oran’s, both of which, though sadly mutilated, still show the general plan of the church and domestic edifices of these monastic establishments more completely than any other Scottish examples. The Church of St. Oran has already been described.[34] The nunnery is also described among the Norman structures.[35]