Donogh O'Brien, 4th Earl of Thomond

Donogh O'Brien, 4th Earl of Thomond and Baron of Ibrickan (died 5 September, 1624) was an Irish nobleman and soldier noted for his loyalty to the Kingdom of Ireland. His long-term objective, achieved after decades, was to obtain an official acknowledgment that County Clare, where his possessions were situated, was part of the province of Munster, to free it from the jurisdiction of the Connaught government under which it had been placed.

Donnchadh(Donogh) mac Conchobhair Ó Briain, was the eldest son of Conor O'Brien, 3rd Earl of Thomond, and his second wife, Una, daughter of Turlough Mac-i-Brien-Ara. Donogh was brought up at Elizabeth's court. There he was residing in 1577, when he was mentioned as Baron of Ibrickan in the new patent granted on 7 October to his father. On his father's death in 1581 he succeeded him as Earl of Thomond; by 1582 he had returned to Ireland.

Thomond was assiduous in his attendance upon the lord-deputy in 1583 and 1584. Albert Pollard, who wrote the biographical entry for Thomond in the Dictionary of National Biography, states that his main object was to obtain an acknowledgment that the county of Clare, where his possessions were situated, was part of Munster, and thus to free it from the jurisdiction of the Connaught government, under which it had been placed previous to his father's death; but it was many years before he succeeded.

In 1584 he was one of the commissioners who established the agreement that tanistry and the law of partible succession should be abolished in Connaught, and a tax of ten shillings a quarter be paid on land. Next year he attended the parliament held at Dublin in April. In 1589 he was active in subduing rebellious Irish in the mountains; and when Tyrone's rebellion broke out in 1595, he played a major part in its suppression. In command of a large force, he passed the River Erne in July and invaded Hugh Roe O'Donnell's country, but retreated in August when a truce was signed. In the following September he was detached by Sir William Russell, with five companies of foot and 145 horse, for the defence of Newry. In 1597 he served in Thomas Burgh, 5th Baron Borough's campaign, but early next year went to England, arriving in London on 19 January 1598; there he remained most of the year as a courtier.

Meanwhile, Tyrone's victory at the battle of Yellow Ford was followed by the spread of disaffection into Thomond's country. Teige O'Brien, Thomond's next brother, entered into communication with Tyrone's son, and joined the rebels. In 1599 O'Donnell invaded Clare, ravaging the country, capturing most of the castles, and making a prisoner of Thomond's youngest brother, Daniel O'Brien, afterwards first Viscount Clare, who had been left to defend it. Thomond returned from England, and after spending three months with his kinsman, the Earl of Ormonde, in collecting forces, he invaded Clare to revenge his brother's imprisonment and recover his possessions. He procured ordnance from Limerick, and laid siege to the castles that resisted, capturing them after a few days' fighting; at Dunbeg, which surrendered immediately, he hanged the garrison in couples on trees. The invaders were completely driven out of Clare and the neighbouring country, and the loyalists had their strongholds restored to them. During the rest of 1599 Thomond accompanied Robert Devereux, 2nd Earl of Essex on his progress through Munster, but left him at Dungarvan and returned to Limerick, being appointed governor of Clare on 15 August, and made a member of the privy council on 22 September.

During 1600 Thomond was constantly occupied in the war. In April he was with Sir George Carew, and narrowly escaped capture with the Earl of Ormonde; he saved Carew's life and enabled them both to cut their way through their enemies, though Thomond was wounded. He was present at an encounter with Florence MacCarthy Reagh, and assisted at his submission in May. In June he was commanding in Clare and opposing O'Donnell's raids. He entertained the lord-deputy at Bunratty and marched out to oppose Tyrone's progress southwards, but no battle was fought, and Tyrone returned without having even seen an enemy. Next year, after holding an assize at Limerick in February, at which sixteen men were hanged, Thomond again went to England, probably with the object of obtaining the governorship of Connaught and of securing the union of Clare with Munster. He delayed there, then set out by Bristol, and, landing at Castlehaven on 11 November 1601, proceeded to Kinsale, where he took a prominent part in the siege. After the surrender of Kinsale he proceeded through Munster, established himself in Bere Island. He was in command at the siege of Dunboy, and hanged fifty-eight of the survivors.

Until June 1602 Thomond was constantly with the army. He then again visited England, and, as a recompense for his services, his request for the transfer of Clare was granted, though the lord-deputy and privy council of Ireland were opposed to the measure. He returned in October. On 30 July 1604 he was appointed constable of Carlow, and on 6 May 1605 he became President of Munster. In 1613 he strongly upheld the Protestant party in opposition to the recusants in the disputes about the speaker of the Irish House of Commons; and on 17 May 1619 he was reappointed governor of Clare. He became one of the sureties for Florence MacCarthy Reagh, who had been imprisoned since his surrender in 1600, and who dedicated to Thomond his work on the antiquity and history of Ireland. He died on 5 September 1624, at Clonmel, and was buried in Limerick Cathedral, where a monument with inscription was erected to his memory.

Pollard concludes that he was one of the most influential and vigorous of the Irish loyalists; and, though his devotion and motives were sometimes suspected, Carew wrote that "his services hath proceeded out of a true nobleness of mind and from no great encouragement received" from the court.

He married, first, Ellen or Helen, daughter of Maurice Roche, 6th Viscount Fermoy, and Eleonor FitzGerald, who died in 1597; by her he had one daughter, married to Cormac, son and heir of Lord Muskerry. His second wife, who died on 12 January 1617, was Elizabeth, fourth daughter of Gerald FitzGerald, 11th Earl of Kildare and Mabel Brown; by her he had Henry O'Brien, 5th Earl of Thomond, and Barnabas O'Brien, 6th Earl of Thomond. Thomond's second brother, Teige, was long imprisoned in Limerick on account of his rebellion, but was released on protesting his loyalty; after another imprisonment he joined in O'Donnell's second invasion of Clare in 1599, and was killed during Thomond's pursuit of the rebels.