[1] Murrough visited Charles I at Oxford in 1644, but found it expedient to submit to the English Parliament the same year as the Parliamentarians being masters of sea, were the only people who could help the Munster Protestants defend themselves against Roman Catholics.

He became the 6th Baron on the death of his father in 1624;[5] his wardship was given to Patrick FitzMaurice, and the custody of his property to Sir William St. Leger, Lord President of Munster, whose daughter Elizabeth he married.

[2] They had three sons: —and four daughters: The great Irish rebellion began on 23 October 1641, and in December Inchiquin accompanied the president in an expedition against the Leinster rebels who were harassing Waterford and Tipperary.

[17] In April 1642, during the siege of Cork by Viscount Muskerry with four thousand men, Inchiquin, "one of the young and noble-spirited commanders," led a sally of two troops of horse and three hundred musketeers, which broke up the Irish camp for a time.

Inchiquin gave a commission to the commandant at Youghal as early as 26 July 1642 to execute martial law thereupon both soldiers and civilians, and his dealings with the town are recorded in the "Council Book".

[22] At the end of May 1643 he took the field with four thousand foot and four hundred horse, but could only threaten Kilmallock, "for want of provisions and money for the officers", and he begged the Earl of Cork to lend or borrow £300 for victualling Youghal.

Another small force was sent to Fermoy, but suffered a crushing defeat at Cloghleagh on 4 June from a body of horse under James Tuchet, 3rd Earl of Castlehaven, who had been specially sent by the Kilkenny confederation.

[26] The cessation of arms for a year, which Ormonde, at the king's command, concluded with the confederates on 15 September 1643, was formally approved by Inchiquin in a document which he signed along with Marquess of Clanricarde and many other persons of distinction,[27] but he did not think it really favourable to the cause of the Irish Protestants.

The immediate result was that a great part of the force under his orders was sent to serve the king in England, two regiments being assigned to Lord Hopton in Sussex,[28] and the rest scattered under various leaders.

[31] Inchiquin went to Oxford early in February 1644, his main object being to get the king's commission as president of Munster; but a formal promise had already been given to Jerome Weston, 2nd Earl of Portland, who received a patent for life on 1 March.

[36] During the next few weeks he edged away both from the Confederate Catholics and from Ormonde, and on 25 August 1644 he informed the latter that a parliamentary ship had reached Youghal, that the town had embraced that cause, and that he should have to do the same; and he entreated him to put himself at the head of the Protestant interest.

[39] The truce expired 10 April 1645, and Castlehaven at once invaded Munster with six thousand men, reducing most of the detached strongholds easily, capturing Inchiquin's brother Henry, and ravaging the country to the walls of Cork.

[40] Inchiquin sent in many supplies by sea from Cork, in which he had the help of Vice-admiral John Crowther's squadron; a larger convoy was sent by the English Parliament after the Battle of Naseby, and in September Broghill, who had been to England for help, finally relieved the place.

At the end of the year, Inchiquin induced his kinsman, Barnabas O'Brien, 6th Earl of Thomond, to admit parliamentary troops into Bunratty Castle, near Limerick, but it was retaken in the following July.

[51] At the beginning of November, fearing a juncture between the Munster chief and the victorious Michael Jones, the Confederates sent Lord Taafe into the county of Cork with six thousand foot and twelve hundred horse.

Owen Roe O'Neill advanced in July as far as Nenagh, his object being to reach Kerry, whose mountains were suited to his peculiar tactics, and whose unguarded inlets would give him the means of communicating with the continent; but Inchiquin,[59] forced him back to Ulster.

Ormonde, who was still the legal lord-lieutenant, landed at Cork on 30 September, and he and Inchiquin thenceforth worked together, Clanricarde and Lord Preston siding with them as against the Nuncio Rinuccini and the Ulster general O'Neill.

The Munster army had been buoyed up with the hopes of pay at Ormonde's arrival, but he had only thirty pistoles, and some of the disappointed cavalry left their colours with a view to joining either Jones or O'Neill.

Inchiquin returned to Leinster at the end of October, and on 1 November was at the head of some three thousand men, chiefly horse, and he advanced through the hills from Carlow to attack about half that number of Cromwell's soldiers who had been left sick in Dublin.

[67] The English or Protestant inhabitants of Cork, "out of a sense of the good service and tender care of the Lord Inchiquin over them," asked Cromwell to see his estate secured to him and his heirs, but to this the victor "forbore to make any answer".

[72] Henry Cromwell joined Broghill, and defeated these new levies which consisted chiefly of Englishmen towards the end of the month; and Inchiquin, after plundering most of the county Limerick, crossed the Shannon into Clare "with more cows than horses".

In their declaration made at Jamestown on 12 August 1650, they accused Inchiquin of betraying Munster, and charged both him and Ormonde with spending their time west of the Shannon "in play, pleasure, and great merriment".

Bagwell wrote that Clarendon not unfairly summed up the case by saying that "when these two lords had communicated each to other (as they quickly did) the excellent addresses which had been made to them, and agreed together how to draw on and encourage the proposers, that they might discover as much of their purposes as possible, they easily found their design was to be rid of them both".

[75] The choice of Heber MacMahon, Bishop of Clogher, as O'Neill's successor brought disaster, and Ormonde, accompanied by Inchiquin and some forty other officers, left Ireland, and, after three weeks' tossing, landed safely at Perros Guirec in Brittany.

[78] On 11 May he was made one of the royal council, "of whose company," Edward Hyde wrote, "I am glad; who is, in truth, a gallant gentleman of good parts and great industry, and a temper fit to struggle with the affairs on all sides that we are to contend with".

The English Parliamentary envoy William Lockhart says the lady was persecuted, and that he had given her a pass to England without consulting the Protector's government, for fear of the French Protestants, who were witnesses of her sufferings.

[89] The great question was as to the custody of her young son, Lord O'Brien, Henrietta Maria and the Catholic party favouring Inchiquin's claim, and the Protestants taking the other side.

Lockhart's diplomacy triumphed, and Inchiquin, who had violently carried the boy off from the English embassy, was ordered to restore him on pain of being banished from France and losing all his commissions and allowances.

[94] The negotiations which led to the Peace of the Pyrenees destroyed his chances in Catalonia; but Cardinal Mazarin connived at his going with Count Schomberg to help the Portuguese, and he started for Lisbon in the autumn of 1659.

[98] Inchiquin was generally in attendance on the Queen mother, either in London or Paris, and on 23 June 1662 it is noted that "this famous soldier in Ireland" sailed as general-in-chief of the English expeditionary force sent by Charles to help the Portuguese; that he landed at Lisbon on 31 July with two thousand foot and some troops of horse, and that he made a short speech to his men.