At this time the Anglo-Norman barons who had come over at the time of Henry II.'s Invasion, nearly twenty years before, had settled down in various parts of Ireland: and they were constantly encroaching on the lands of the Irish and erecting strong castles everywhere; while the Irish chiefs as we have already said, resisted as far as they were able, so that there was much disturbance all over the country. Cahal was a brave and active king, and took a leading part in fighting against the barons.
After he had reigned over Connaught in peace for eight or nine years, trouble came again. There was at this time, settled in Limerick, a powerful Anglo-Norman baron, William de Burgo, to whom a large part of Connaught had been granted by King Henry II. This man stirred up another of the O'Conors to lay claim to the throne in opposition to Cahal, promising to help him: and now Connaught was again all ablaze with civil war. Cahal was defeated in battle, and fled to Ulster to Hugh O'Neill, prince of Tyrone, who took up his cause. Marching south with his own and O'Neill's men, he attacked his rival, but was defeated, and again fled north. He soon made a second attempt, aided this time by Sir John de Courcy (for whom see page 190): but he and De Courcy were caught in an ambush in Galway by the rival king, who routed their army. In this fight De Courcy very nearly lost his life, being felled senseless from his horse by a stone. Recovering in good time however, he and Cahal escaped from the battlefield, and fled northwards.
Cahal of the Red Hand, in no way cowed by these terrible reverses, again took the field, after some time, aided now by De Burgo, who had changed sides. A battle was fought near Roscommon, in which the rival king was slain; and Cahal once more took possession of the throne. From this period forward he ruled without a native rival; though a few years later, he was forced to surrender a large part of his kingdom to King John, in order that he might secure possession of the remainder.
But he was as vigilant as ever in repelling all attempts of the barons to encroach on his diminished territory. Thus when in 1220 the De Lacys of Meath, a most powerful Anglo-Norman family, went to Athleague on the Shannon at the head of Lough Ree, where there was a ford, and began to build a castle at the eastern or Leinster side, in order that they might have a garrison in it always ready to attack Connaught, Cahal promptly crossed the river into Longford, and so frightened them that they were glad to conclude a truce with him. And he broke down the castle, which they had almost finished.