Mac Murchada (MacMurrough), Murchad (d. 1172), king of Uí Cheinnselaig, the fourth son of Donnchad Mac Murchada (d. 1115), king of Leinster, would have been very young when his father marched out of Ferns in 1115 to challenge the might of the armies of Muirchertach Ua Briain (qv) (d. 1119), high-king of Ireland. At Dublin, Donnchad and his ally, Conchobar Ua Conchobair Fhailge (qv) (d. 1115), were killed by the forces of Domnall Ua Briain (qv) and the Ostmen, who reputedly buried Donnchad with a dog in the floor of their assembly house; a brother of Murchad was also killed by the Uí Briain (O'Briens) later that year. The successive kingships of Diarmait son of Énna Mac Murchada (d. 1117) and Murchad's brother Énna Mac Murchada (1117–26) saw a revival of the dynasty's fortunes. Murchad is first heard of during the reign as king of Leinster of his brother Diarmait Mac Murchada (qv) (d. 1171), whom he served as an effective lieutenant.
In 1141 Diarmait moved against his enemies in Leinster, the Uí Dúnlainge allies of Tairdelbach Ua Conchobair (qv) (d. 1156), high-king of Ireland. The execution of the plan was entrusted to Murchad. Acting on Diarmait's orders, he lured many of the Uí Dúnlainge nobles, of the leading families of Mac Fáeláin, Ó Tuathail and Mac Gilla Mo Cholmóc, to a meeting, where he and his men took them by surprise, killing seventeen of them and blinding many more. After this bloody affair, no mention is made of Murchad in the records, which indicates his general satisfaction with the rule of his brother. He next appears, with his son Muirchertach Mac Murchada (d. 1193), as witness to two charters of Diarmait (1162 and 1165) in favour of the Cistercian foundation at Killenny, by which time, apparently, he was becoming alienated from the king. The source of his discontent may have been that Diarmait favoured his own sons to succeed him.
A country-wide crisis in 1166 presented Murchad and Muirchertach with their chance to depose Diarmait. In that year the high-king Muirchertach Mac Lochlainn (qv) (d. 1166), ally of Diarmait Mac Murchada, blinded Eochaid Mac Duinn Sléibe, foster son of Donnchadh Ua Cerbaill (qv) of Airgialla (Oriel). Ua Cerbaill then gave his allegiance to Ruaidrí Ua Conchobair (qv) (d. 1198), who with other confederates marched to Dublin, where he was acknowledged as high-king. Ua Cerbaill and the Uí Dúnlainge princes of west Leinster submitted to Ruaidrí, and the high-king's forces attacked the Meic Murchada in their heartland of Uí Chennselaig. Failing to stop them at the pass of Fid Dorcha, Diarmait and Murchad fell back upon their capital of Ferns, setting it aflame before attempting to muster forces elsewhere in their kingdom. After a short but brutal struggle, Diarmait was forced to submit to Ruaidrí.
While the high-king was campaigning in Ulster, Diarmait attempted to reassert himself over Leinster by encouraging Ó Braenáin to kill MacGillamocholmeoc, the rebel lord of Uí Briúin Chualann. This act sparked a second revolt by the Uí Dúnlainge, who with the Ostmen of Dublin swept into Uí Cheinnselaig. Diarmait's vassals, including Murchad and Murchad O'Byrne (d. 1172), deserted en masse, making further resistance by the Meic Murchada futile. Diarmait fled for assistance to Henry II (qv) and Uí Cheinnselaig was divided between Murchad and Domnall Mac Gilla Pátraic (qv) (d. 1185), king of North Osraige. In return for his portion of the kingdom, Murchad and his kinsmen handed over some seventeen hostages to the new high-king. But in 1167 Diarmait returned with English troops and reconquered Uí Cheinnselaig, and Murchad submitted to his brother. It may have been at this time that Murchad married one of the newcomers, a woman of the Barry family. By 1171 Diarmait, with the aid of his son-in-law, Richard de Clare (qv) (d.1176), earl of Pembroke and Striguil, had become a serious contender for the high-kingship of Ireland, but his sudden death at Ferns in May 1171 transformed the political landscape in Leinster.
The Leinster nobility now saw their chance to revolt against Diarmait's son Domnall Cáemánach Mac Murchada (qv) (d. 1175) and his English allies. Murchad led this rebellion and claimed the kingship of Uí Cheinnselaig, rejecting Domnall's succession and that of Clare. At first the Leinstermen enjoyed considerable success, won control over much of Uí Cheinnselaig and Leinster, and forced Domnall to flee to Clare at Dublin. In September 1171 Archbishop Lorcán Ua Tuathail (qv) (d. 1180) and Murchad led a force to Dalkey to assist Ruaidrí Ua Conchobair's blockade of the English in Dublin. After the English broke the blockade, the Leinster army withdrew intact, but their retreat encouraged the English to make wide-ranging attacks on Leinster and raid Murchad's heartland in Uí Cheinnselaig. Bereft of Ruaidrí's protection, many of the Leinster nobility bowed to the political reality and welcomed the arrival in Ireland of Henry II in autumn 1171. But Murchad and his son Muirchertach, perhaps realising that it would avail them nothing, did not join the Irish princes who sought Henry's protection; and as they had suspected, Henry confirmed Leinster to Clare and granted its sub-kingdoms to the English adventurers. In early 1172 Murchad was lured into a trap by a detachment of Henry's troops and killed. Muirchertach burned Ferns, probably in retaliation for his father's death. However, according to the almost contemporary chanson de geste known as the Song of Dermot and the earl, Clare and Muirchertach later agreed a settlement whereby Muirchertach was recognised as king of Uí Cheinnselaig, while Domnall Cáemánach Mac Murchada was appointed seneschal of the Irish of Leinster.
Muirchertach's satisfaction with this deal is proved by his subsequent actions: in 1172–3, he visited Winchester with the burgesses of Wexford at Henry II's expense. But it was less to Domnall's liking. The Annals of Tigernach record that in 1173 Domnall's son ambushed Clare's soldiers, while MacCarthy's Book mentions that Domnall himself defeated the earl and his forces in battle, inflicting 200 fatalities. In 1175 Domnall, described by now as king of Leinster, was killed, either (according to the Annals of the Four Masters) by Ó Nualláin of Forth while trying to enforce his dual mandate, or (in the Annals of Tigernach) by the Uí Niallain of Offaly. After Domnall's death east Leinster gradually became more peaceful, and Uí Cheinnselaig was left alone by the settlers, which eased Muirchertach's relations with Clare. Muirchertach's epithet ‘na Maor’ (meaning ‘of the stewards’ or ‘rent collectors’) may indicate that he inherited Domnall's position as seneschal of the Irish of Leinster. He seems also (probably with Clare's approval) to have taken Ferns as his capital. In 1176 he campaigned for the earl against Domnall Mór Ua Briain (qv) (d. 1194), king of Thomond, in Limerick.
A survivor of a very turbulent period in Irish politics, Muirchertach died as king of Uí Cheinnselaig at Ferns in 1193. He was succeeded by one of his two sons (Domnall Remor or Diarmait Muimnech); his successor may have been the Mac Murchada who perished in the English campaign of 1196 against the Irish of Tyrone.