Another synod was held in the year 1158, at Trim. Derry was then erected into an episcopal see, and Flahertach O'Brolchain, Abbot of St. Columba's Monastery, was consecrated its first bishop. The bishops of Connaught were intercepted and plundered by Dermod's soldiers; they therefore returned and held a provincial synod in Roscommon.
In 1162 St. Laurence O'Toole was chosen to succeed Greine, or Gregory, the Danish Archbishop of Dublin. He belonged to one of the most noble ancient families of Leinster. His father was chieftain of the district of Hy-Muirahy, a portion of the present county Kildare. St. Laurence had chosen the ecclesiastical state early in life; at the age of twenty-five he was chosen Abbot of St. Kevin's Monastery, at Glendalough. The Danish Bishop of Dublin had been consecrated by the Archbishop of Canterbury, but the saint received the episcopal office from the successor of St. Patrick. A synod was held at Clane the year of his consecration; it was attended by twenty-six prelates and many other ecclesiastics. The college of Armagh was then virtually raised to the rank of a university, as it was decreed that no one, who had not been an alumnus of Armagh, should be appointed lector or professor of theology in any of the diocesan schools in Ireland. Indeed, the clergy at this period were most active in promoting the interests of religion, and most successful in their efforts, little anticipating the storm which was then impending over their country.
In 1166 the Irish Monarch, O'Loughlin, committed a fearful outrage on Dunlevy, Prince of Dalriada. A peace had been ratified between them, but, from some unknown cause, O'Loughlin suddenly became again the aggressor, and attacked the northern chief, when he was unprepared, put out his eyes, and killed three of his leading officers. This cruel treachery so provoked the princes who had guaranteed the treaty, that they mustered an army at once and proceeded northwards. The result was a sanguinary engagement, in which the Cinel-Eoghan were defeated, and the Monarch, O'Loughlin, was slain. Roderick O'Connor immediately assumed the reins of government, and was inaugurated in Dublin with more pomp than had ever been manifested on such an occasion. It was the last glittering flicker of the expiring lamp. Submission was made to him on every side; and had he only possessed the ability or the patriotism to unite the forces under his command, he might well have set all his enemies at defiance. An assembly of the clergy and chieftains of Ireland was convened in 1167, which is said to have emulated, if it did not rival, the triennial _Fes_ of ancient Tara. It was but the last gleam of sunlight, which indicates the coming of darkness and gloom. The traitor already had his plans prepared, and was flying from a country which scorned his meanness, to another country where that meanness was made the tool of political purposes, while the unhappy traitor was probably quite as heartily despised.