The Abbey of St Thomas the Martyr owes its existence to two events: the murder of Thomas Becket in December 1170, and King Henry II’s subsequent incursion into Ireland less than a year later. In a paper recorded at a Dublin City Council symposium on The Abbey of St Thomas the Martyr, UCD historian Michael Staunton shows how Henry II’s invasion of Ireland in 1171 ultimately led to his reconciliation with Thomas, and the founding of an abbey in Becket’s honour in 1177.