Why more isn’t written on the medieval conquest of Ireland is surprising to me. It would make for a sweeping tale.
It all began 1126 when Énna Mac Murchada, King of Leinster, died unexpectedly and the throne passed to his younger brother, Diarmait Mac Murchada (anglicized to Dermot MacMurrough). Dermot was approximately 16 years old when he became king. It was a volatile time in Ireland, his father was killed by the Viking king of Dublin, who was also his cousin. Strife from competing kingdoms and Viking invaders had left Ireland war torn and weary. Kings had many rivals. Not so long before Dermot’s birth there were approximately 500 kings claiming dominion over parts of Ireland, which had a population of about 500,000.
Turlough Mór O’Connor (Toirdhealbhach Ua Conchobhair), King of Connacht and High King of Ireland (1120–1156), saw the young Dermot as a rival. He had a right to worry, two of his brothers had been killed in battle, one murdered and one deposed as king. His father had been intentionally blinded by his adopted son, and the kingship usurped. So Turlough sent another king, Tiernan O’Rourke (King of Breifne) to oust Dermot. Raids, starvation and skirmishes led to Dermot losing the kingdom. However, in 1132 he was able to regain his throne with the help of his clansmen. A hostile peace ensued and in 1152 Dermot aided Turlough in a raid against Tiernan O’Rourke. Dermot abducted Tiernan O’Rourke’s wife, Derval, who is sometimes referred to as the ‘Helen of Ireland,’ for her role in the Norman Invasion. However, this idea has be downplayed, perhaps mostly because of the gap between this event and the next.
In 1166 Tiernan invaded the kingdom of Leinster and the High King of Ireland, who was now Rory O’Connor, son of Turlough, dethroned Dermot, taking his land and forcing him to flee to Wales. In England he was granted soldiers by Henry II. Many of the soldiers were Normans, who came over in 1066, and were living in southern Wales. The term Cambro-Norman Invasion is now a more accepted term than Anglo-Norman Invasion for this reason.
One of the most famous Cambro-Normans was Richard de Clare, who spearheaded the invasion. He developed the nickname of Strongbow, after his death, due to his prowess with the longbow. Most soldiers fought for the promise of land and fortune. Today the invasion of the Welsh can be seen in surnames and town names as many resettled in Ireland. Richard de Clare was married to Dermot’s daughter, Aoife, or Eva and all the lands and the kingship of Leinster became his after Dermot’s death.
While Dermot was soliciting aid in England, Rory O’Rourke became High King of Ireland. He did not take notice of their successful siege to Wexford (1169). After raiding the Kingdom of Ossuary, and a series of successful raids reaching further north, Richard de Clare turned to Tara in the Boyne Valley, the political seat of Ireland. Then they turned their attention to Leinster, conquering and subduing Dublin as well.
IN 1171 another, larger invasion was launched by Henry II and all the Irish kings submitted to King Henry II. The Treaty of Windsor in 1175 gave most of Ireland to England, but with some clans still controlling their lands. However the treaty did not last and more territory was conquered by the English until the whole island was subdued. Henry II added King of Ireland to his titles and the island remained under English control for more than 700 years.
Now as for Dermot, he died shortly after, having been devastated by the news that Rory O’Rourke had his son killed during the invasion. He later became known as Diarmait na nGall, or Dermot of the Foreigners, and was see in a very poor light. Though some scholars point out that his ambition, gaining his throne back, was his main goal and that he did not, and maybe could not see the consequences of his actions. His descendants, through his daughter’s marriage to Richard de Clare stayed in the nobility for many centuries afterwards.