After Columba's death, the monastery of Iona appears to have been the acknowledged head of all the monasteries and churches which his mission had founded in Scotland, as well as of those previously founded by him in Ireland. It was a centre of light and life, but the monks were not permitted to pursue their work unmolested. The monastery was burned and plundered by the sea-pirates in 795, 798, and 802; in 806 sixty-eight of the community were ruthlessly slain. The monks remaining were filled with fear, and before 807 the relics of St. Columba were carried away to Ireland, and enshrined at Kells. In 818 they were brought back, and the monastery at Iona was rebuilt with stone. The Danes, however, granted little respite, and in 878 the relics were again removed, and were probably placed first at Dunkeld and afterwards at Abernethy,[193] where the primacy was successively established, and a memorial of which exists in the Abernethy round tower. The plundering continued at intervals, and the buildings were more or less ruinous till about 1074, when Queen Margaret "restored the monastery, ... rebuilt it, and furnished it with monks, with an endowment for performing the Lord's work." "One of the present buildings," said the late Duke of Argyll--"the least and the most inconspicuous, but the most venerable of them all--St. Odhrain's Chapel, may possibly be the same building which Queen Margaret of Scotland is known to have erected in memory of the saint, and dedicated to one of the most famous of his companions. But Queen Margaret died in A.D. 1092, and therefore any building which she erected must date very nearly five hundred years after Columba's death; that is to say, the most ancient building which exists upon Iona must be separated in age from Columba's time by as many centuries as those which now separate us from Edward III. But St. Odhrain's Chapel has this great interest--that in all probability it marks the site of the still humbler church of wood and wattles in which Columba worshipped."[194] Shortly afterwards the island passed into the possession of Magnus Barefoot, King of Norway, and in 1099 the old order culminated in the death of Abbot Duncan, the last of the old abbots. Under the bishopric of Man and the Isles, the monastery became subject to the Bishop of Drontheim till 1156, when Somerled won it, and once more restored the connection between Iona and Ireland by placing the monastery under the care of the Abbot of Derry. In 1164 the community was represented by the priest, the lector, the head of the Culdees, and the Disertach or the head of the disert for the reception of pilgrims.[195] Somerled appears to have rebuilt the ruined monastery on a larger scale, and about 1203 the Lord of the Isles (Reginald) adopted the policy of the Scottish kings, and founded at Iona a monastery of Benedictine monks (Tyronenses), and at the same time a nunnery for Benedictine nuns, of which Beatrice, sister of Reginald, was first prioress.