Diarmait Mac Murchada - Exile and Return

Exile and Return

In 1166, Ireland's new High King and Mac Murchada's only ally Muirchertach Ua Lochlainn had fallen, and a large coalition led by Tigernán Ua Ruairc (Mac Murchada's arch enemy) marched on Leinster. The High King deposed Mac Murchada from the throne of Leinster. Mac Murchada fled to Wales and from there to England and France seeking the support of Henry II of England in the recruitment of soldiers to reclaim his kingship. On returning to Wales, Robert Fitz-Stephen helped him organise a mercenary army of Norman and Welsh soldiers, including Richard de Clare, 2nd Earl of Pembroke, alias Strongbow.

In his absence Ruaidrí Ua Conchobair (son of Mac Murchada's former enemy, the High King Turlough Mór O'Connor) had become the new High King of Ireland. Mac Murchada planned not only to retake Leinster, but to oust the Uí Conchobair clan and become the High King of Ireland himself. In 1167 he quickly retook Dublin, the Kingdom of Ossory and the Norse-Gaelic settlement of Waterford. Within a short time, all Leinster was again in his control. He then marched on Tara (the political capital at the time) to oust Ruaidrí. Mac Murchada gambled that Ruaidrí would not hurt the Leinster hostages which he had (including Mac Murchada's eldest son, Conchobar Mac Murchada). However Ua Ruairc forced his hand and they were all killed.

Diarmait's army then lost the battle. He sent word to Wales and pleaded with Strongbow to come to Ireland as soon as possible. Strongbow's small force landed in Wexford with Welsh and Norman cavalry thereby precipitating the Norman invasion of Ireland. The Cambro-Norman barons and knights quickly took over both Waterford and Wexford. The capture of Dublin followed soon after. MacMurrough was devastated after the death of his son, Domhnall, retreated to Ferns and died a few months later.

Strongbow married Dermot's daughter Aoife of Leinster in 1170, as she was a great heiress, and as a result much of his (and his followers') land was granted to him under Norman law but contrary to Brehon law. The marriage was imagined and painted in the Romantic style in 1854 by Daniel Maclise.

The scholar Áed Ua Crimthainn was probably Diarmait's court historian. In his Book of Leinster, Áed seems to be the first to set out the concept of the rí Érenn co fressabra, the "king of Ireland with opposition", later more widely adopted. This described Diarmait's ambitions and the achievements of his great-grandfather Diarmait mac Maíl na mBó.