In 1170, Affe, daughter of Diarmait Mac Murchada, married Richard FitzGilbert de Clare, the Anglo-Norman baron better known as Strongbow. Their union fulfilled one half of the promise made by Mac Murchada in return for Strongbow’s help in regaining his lost kingdom of Leinster. Strongbow’s succession to that kingship upon Mac Murchada’s death in 1171 fulfilled the other half.
Strongbow’s succession has traditionally been seen as running contrary to both Irish and English practice. English law held that only in the absence of male heirs could a man succeed in right of his wife, but Mac Murchada had at least one son living in 1171. It has been suggested, however, that Mac Murchada may have regularized his marriage with Affe’s mother under canon law, thereby rendering Affe his only legitimate offspring alive at that time. In terms of Irish tradition, it has been further suggested that a precedent of sorts for Strongbow’s succession lay in the twelfth-century phenomenon of imposing dynasts upon thrones to which they had no ancestral claim. Marrying the daughter of one’s predecessor was, moreover, a common characteristic of peaceful transfers in Irish dynastic control.
Styling herself "Countess of Ireland," Affe issued charters concerning both her native Leinster and, following Strongbow’s death in 1176, her English dower lands. The earl was initially succeeded by the couple’s son, Gilbert, who died in 1185 while still a minor, leaving their daughter Isabella as sole heiress. In 1189, history repeated itself when William Marshal married Isabella, and succeeded to Leinster in right of his wife.
