The English-ruled Irish government feared that an alliance between the O'Donnell and O'Neill clans would threaten the Crown's control over Ulster, so in 1587 Lord Deputy John Perrot arranged for Hugh Roe's kidnapping.

Along with his father-in-law Tyrone, Hugh Roe O'Donnell led a confederacy of Irish clans in the Nine Years' War, motivated to prevent English incursions into their territory and to end Catholic persecution under Elizabeth I.

In 1600, he suffered various military and personal losses;[b] his cousin Niall Garve defected to the English, which greatly emboldened commander Henry Docwra's troops and forced O'Donnell out of Tyrconnell.

[51] Ultimately the government decided that Hugh Roe must not be allowed to succeed as O'Donnell clan chief,[52][d] and so the Lord Deputy of Ireland, Welsh statesman John Perrot, hatched a plan to kidnap the young noble.

[64] According to 17th-century accounts, Chief Donnell MacSweeney Fanad (Hugh Roe's host) was ashamed that the young noble had missed out on the wine and unwittingly encouraged him to take a small boat to the Matthew.

[77] According to O'Sullivan Beare, O'Byrne and his clansmen immediately set out to rescue Hugh Roe, but their inability to cross a flooded river prevented them from reaching Castlekevin in time.

[77] Ó Cléirigh states the Privy Council were pleased with Hugh Roe's recapture: "they made little or no account of all the hostages and pledges who escaped from them, and they were thankful for the visit which restored him to them again".

O'Gallagher was the Prince's marshal and O'Clery was the ollamh, or scholarly lawyer who presented to him the book containing the laws and customs of the land and the straight, white wand symbolizing the moral rectitude demanded of his judgments and rule."

In early 1593, O'Donnell obtained Hugh McHugh Dubh's submission by taking his last stronghold at Belleek and beheading sixteen of his followers "by train of a feigned treaty of friendship, mediated by Maguire".

[202] By late 1592 the Crown's continual advances into Ireland, as well as the recent executions of chieftains Hugh Roe MacMahon (1590) and Brian O'Rourke (1591) had created a fierce resentment in the Gaelic nobility and Irish clergy.

[210] On 8 April 1593, O'Donnell addressed Irish nobles living in Spain: "I and the other chiefs who have united with me and are striving to defend ourselves, cannot hold out long against the power of the Crown of England without the aid of his Grace the Catholic King.... We have thought it well to send the Archbishop of Tuam [James O'Hely] to treat of this matter with his Majesty".

[213] This exacerbated resentment towards the Crown, and after Willis' first offensive,[212] O'Donnell met with MacGauran, Maguire, Brian Oge O'Rourke[207] and Theobald, Richard and John Bourke at Enniskillen Castle on 8 May.

[q] Historians Nicholas Canny, Michael Finnegan, John J. Silke and Darren McGettigan credit O'Donnell as the confederacy's driving force until Tyrone's break into open rebellion.

These urged him to disperse his forces, to shire Tyrconnell, to stop aiding O'Rourke and Maguire, to re-edify Sligo Castle, to pay annual rents to the Crown as his father had done, and to confess the extent of his dealings with Spain.

[310] The Irish victory at the Yellow Ford was highly distressing to the English Privy Council, and after much hesitation Elizabeth I appointed her royal favourite Robert Devereux, 2nd Earl of Essex, as the new Lord Deputy.

By this time Iníon Dubh had been in Scotland for two months gathering redshanks—as Clifford's forces had been easily defeated, O'Donnell notified his mother that the redshanks were unnecessary, and she returned to Tyrconnell in January 1600 with gunpowder instead.

Niall Garve's brothers and an estimated one thousand Clan O'Donnell warriors also joined his efforts to wrest the White wand away from Hugh Roe with the support of the Crown.

"[170] O'Sullivan Beare, on the other hand, was more nuanced in his assessment, "Garve was a man of great spirit and daring, skilled in military matters and had many of the men of Tyrconnell on his side, fortified by whose aid and valour he did not decline a fight with the Catholics in the open.

Hundreds of the besieged were blown to atoms; others, among the rest Nial's own brother, were crushed to death by masses of the rent masonry; and all that night, while the woodwork blazed like a red volcano, in whose glare friend and foe were distinctly visible to each other, O'Donnell's swordsmen pressed the survivors back across the trenches into the flames, where upwards of a thousand of them perished miserably.

Next morning Nial proceeded unobserved by O'Donnell's troops, along the strand to Magherabeg, and returned, under cover of the guns of the English war vessel, with the soldiers he had left in that place, determined to maintain himself to the last among the smoldering ruins.

O'Donnell immediately shifted his camp nearer to Donegal, and continued the siege till October; when, being informed that the Spaniards had landed at Kinsale, he struck his tents and marched to their assistance.

Under the command of General Don Juan del Águila finally landed and was besieged by the English Army inside the walled city of Kinsale – at virtually the opposite end of Ireland from the Northern clans – in September 1601.

"[366] Meanwhile, as the defeated Irish clans gathered in a conference at Innishannon, an outraged and heartbroken Hugh Roe O'Donnell announced his plans to travel to Spain to seek further reinforcements from King Philip III.

[376] In the middle of 1602, Hugh Roe O'Donnell, suffering from "anguish of heart and sickness of mind", finally left for Valladolid "to go into the King's presence again to learn the cause of the delay."

In September 1607, Rory and Tyrone, accompanied by their families, household staff, followers and fellow Irish nobles, permanently left Ireland for Catholic Europe in what is known as the Flight of the Earls.

Historian and folklorist Tony Nugent accordingly lists twelve Mass rocks located throughout County Donegal that were used for illegal religious worship over the following centuries in defiance of the law, the Redcoats and the priest hunters.

The grave of Friar Rory O'Hegarty, who was captured and summarily executed by priest hunters while offering Mass near Buncrana in 1711 and buried where he fell, remains a local site of Christian pilgrimage.

[438] Following the Irish War of Independence, the ascendant Fianna Fail political party began a policy of granted courtesy recognition as Chief of the Name to the senior male descendants of the Gaelic nobility of Ireland.

It is to be feared, that for the same reason, they frequently omitted what might be disagreeable to their patrons, or scandalous to the Church; thus they were guilty of anachronisms and various mistakes, which have the effect of throwing discredit upon the works so transmitted to us, as disproving apparently their claim to antiquity.

[476] Franciscan Donagh O'Mooney, who knew O'Donnell personally, described him as of "middle height, ruddy, of comely face, and beautiful to behold... his voice was like the music of a silver trumpet".