1150. He was fostered or brought up by Tadhg O'Concheanainn of the Ui Diarmada, co. Galway.
According to a story once well known in Connaught, Cathal was the natural son of King Turlough by Gearrog Ni Morain, a native of the Owles, co. Mayo. Turlough's queen sought by witchcraft to prevent Gearrog from giving birth to a child, but the requisite incantation was not complete till after a right-hand presentation had taken place. None the less, Gearrog's labour was retarded by the queen's spell for several days. In the meantime the rumour reached the queen that Gearrog had given a son to the king of Connaught. She thereupon dissolved the spell, and Cathal's birth was completed; but his right hand remained ever after red, whence his cognomen, Croibhdheirg, i.e. red-handed. The local story goes on to tell that Cathal was brought up far away, and had to earn his living by field work among the farm labourers of Leinster, until a herald arrived with the news that the king of Connaught was dead, and, according to information previously supplied him by the chief clansmen, recognised Cathal as the dead king's son by his red hand. Cathal accordingly flung down his sickle, saying, ‘Slan leat a chorrain, anois do'n chloidheamh’ (‘Farewell to thee, oh sickle; now for the sword’), went home, and was inaugurated king of Connaught. A well-known Irish saying applied to a last farewell, ‘Slan Chathail faoi an tseagal’ (‘Cathal's farewell to the rye’), alludes to this story.
There is no passage in the ‘Annals’ which supports the view of Cathal's illegitimacy, nor did he become king of Connaught till 1201, when his elder brother, king Roderic, and Roderic's eldest son, king Cathal Carrach, were both dead. But the annalists who were nearly connected with his descendants might possibly have ignored the circumstance. Irish clansmen, on the other hand, when electing a fighting chief, did not probably attach much value to the legitimacy of his birth. But the exact account of his fosterage by the Ui Diarmada, one of the branches of the Sil Muireadhaigh, is a point strongly in favour of his legitimacy. A large superficial nævus may probably have given origin to his cognomen. Another chief, of different race and district, also called Crobhdhearg, occurs in the Irish ‘Annals.’
Cathal opposed his half-brother, king Roderic O'Connor [q. v.], in 1185, and made peace after some fighting, but went to war with Cathal Carrach, Roderic's grandson, in 1190. Tomaltach O'Connor, archbishop of Armagh, endeavoured to make peace between them when visiting Connaught, but without success. Cathal Crobhdhearg sailed up the Shannon after this conference, and was caught in a storm on Lough Ree, in which his son Conchobhar and his friend Aireachtach O'Roduibh, with many others, were drowned. In 1195 he invaded Munster and reached Cashel; but while there Cathal MacDermot seized his boats on Lough Mask, co. Mayo, and ravaged his territory. Cathal returned and made peace, and in 1198 also made peace with Cathal Carrach, who, however, drove him out of Connaught in 1199. He fled to Ulster, and Aedh O'Neill marched into Roscommon on his behalf, but had to retreat, and was overtaken and defeated by Cathal Carrach, aided by William De Burgo, at Ballysadere, co. Sligo. John De Courcy was his next ally, but they were routed at Kilmacduagh, co. Galway. He then tried Munster, and in 1201 marched from Limerick with William De Burgo to Tuam, co. Galway, thence to Oran, Elphin, and Boyle, co. Roscommon. His rival Cathal Carrach was slain in a battle near the abbey of Boyle, and Cathal Crobhdhearg became king of Connaught. He was inaugurated by being placed on the stone of Carnfree, near Tulsk, in the presence of the chiefs of the clans subject to his rule. The ceremony was completed by Donnchadh O'Maelconaire, his senachie, placing a wand in his hand (Kilkenny Archæological Society's Proceedings, 1853, p. 338). He seems to have acknowledged the supremacy of John, king of England (Rymer), and in 1215 received a formal grant of all Connaught, except the castle of Athlone. In 1210 he twice attended John, first at Tiaprait Ulltain, co. Meath, and then at Rathwire, co. Westmeath, gave him four hostages, the form of submission best understood by the Irish. In 1220 he defeated Walter de Lacy, and took the castle of Caladh in Longford. Two Latin letters of Cathal, in which he terms himself Kathaldus Rex Conacie, are preserved in the state paper office. Both were written in 1224, and complain of De Lacy. In the second he asks Henry III to grant him a charter for the possession of Connaught, confirming that which he had had from King John. He died at Bringheol, co. Roscommon, on 28 May 1224, and was buried in the abbey of Knockmoy, co. Galway, which he had founded. His tomb is not preserved, and the monument stated to be his by Dr. Ledwich (Antiquities of Ireland, 2nd ed. p. 520) bears the inscription, ‘Orate pro anima Malachiæ,’ and is that of O'Kelly, who died in 1401, whose wife was Finola O'Connor, and who rebuilt the abbey. Some authorities (Annals of Ulster and Annals of
