Dermod Mac Morough (or Mac Murchad), prince of Leinster, was attached to Dervorghal, wife of Tiernan O’Ruark, another Irish chief, who held the county of Leitrim, with some adjacent districts,—a lady of great beauty, but small virtue, who took advantage of her husband’s being driven into hiding by O’Connor, who was then predominant in Ireland, to elope with her lover. “An outrage of this kind was not always regarded with abhorrence by the Irish; they considered it rather as an act of pardonable gallantry, or such an offence as a reasonable pecuniary compensation might atone for. But the sullen and haughty prince, provoked more by the insolence and treachery of his ravisher than the infidelity of his wife, conceived the most determined animosity against Dermod. He practised secretly with O’Connor, promised the most inviolable attachment to his interest, and prevailed on him, not only to reinstate him in his possessions, but to revenge the insult of Mac Morough, whom he represented, and justly, as a faithless vassal, really devoted to the service of his rival. The King of Connaught led his forces into Leinster, rescued Dervorghal from her paramour, and restored her to her friends; with whom she lived, if not in a state of reconciliation with her husband, at least in that opulence and splendour which enabled her to atone for the crime of infidelity, by the usual method of magnificent donations to the church.”[27] This domestic squabble led to more than usually important results, for the expelled Dermod applied to our Henry II. for assistance, and the conquest of Ireland followed.