He acquired a noble title under English law, becoming 1st Viscount Muskerry and 1st Baron Blarney under letters patent.

[d] MacDermot had conformed to the established religion, in other words: become a Protestant, by adhering to the Church of Ireland.

[40] Her family, the O'Briens, were another Gaelic Irish dynasty, descending, in her case, from Brian Boru, a medieval high king of Ireland.

Charles and Margaret had two sons: —and five daughters (in an unordered list as their birth order is poorly known):[f] MacDermot (MacCarthy's father) fought in Tyrone's Rebellion, also called the Nine Years' War, which lasted from 1593 to 1603.

[69][70] In 1628 Charles I, King of Ireland, England, and Scotland, created him Baron Blarney and Viscount Muskerry.

[74] Muskerry, as he was now, sat in the House of Lords during the two Irish parliaments of King Charles I.

She was the widow of Donal MacCarthy Reagh of Kilbrittain,[86][87] Prince of Carbery in the Gaelic tradition, with whom she had had a son called Charles MacCarthy Reagh of Kilbrittain, who had in 1636 before his father's death,[88][89][90] married Eleanor, one of Muskerry's daughters from his first marriage.

[98] In its first session the parliament unanimously voted four subsidies of £45,000[100] (about £10,100,000 in 2023[101]) to raise an Irish army of 9000[102] for use by the King against the Scots in the Second Bishops' War.

While attending parliament, Muskerry probably stayed at his new townhouse built about that time on Dublin's College Green.

The Commons formed a commission of grievances that gathered evidence for Strafford's abuse of power.

[109] The House of Lords recognised its members who had gone to London as constituting one of its committees[110] and excused their absence.

As the ailing elder brother had died some time before,[44] the title's special remainder did not need to be invoked.