In 1157 a synod was held in the Abbey of Mellifont, attended by the Bishop of Lismore, Legate of the Holy See, the Primate, and seventeen other bishops.  Murtough O’Loughlin, the Monarch of Ireland, and several other kings, were also present.  The principal object of this meeting was the consecration of the abbey church and the excommunication of Donough O’Melaghlin, who had become the common pest of the country.  He was, as might be expected, the particular friend and ally of Dermod Mac Murrough.  His last exploit was the murder of a neighbouring chief, despite the most solemn pledges.  In an old translation of the Annals of Ulster, he is termed, with more force than elegance, “a cursed atheist.”  After his excommunication, his brother Dermod was made King of Meath, in his place.

At this synod several rich gifts were made to the abbey.  O’Carroll, Prince of Oriel, presented sixty ounces of gold.  O’Loughlin made a grant of lands, gave one hundred and forty cows and sixty ounces of gold.  The Lady Dervorgil gave the same donation in gold, together with a golden chalice for the altar of Mary, with gifts for each of the other nine altars of the church.  Dervorgil was the wife of Tiernan O’Rourke, Lord of Breffni, who had been dispossessed of his territories in 1152; at the same time she was carried off by Dermod Mac Murrough.  Her abduction seems to have been effected with her own consent, as she carried off the cattle which had formed her dowry.  Her husband, it would appear, had treated her harshly.  Eventually she retired to the Monastery of Mellifont, where she endeavoured to atone for her past misconduct by a life of penance.

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.