Sir Rory O’Moore (Irish: Ruaidhrí Ó Mórdha), Irish politician and landowner also known Sir Roger O’Moore or O’More or Sir Roger Moore, dies in obscurity on February 16, 1655. He is most notable for being one of the four principal organizers of the Irish Rebellion of 1641.

O’Moore belongs to an ancient Irish noble family descended from Conall Cernach. He is born in either County Laois, around 1600, or more likely at Balyna, his father’s estate in County Kildare.

O’Moore’s uncle, Rory O’More, Lord of Laois, had fought against the English during the Tudor conquest of Ireland. In 1556, Queen Mary I confiscates the O’Mores’ lands and creates “Queens County” (modern-day County Laois). Over 180 family members, who are peaceful and have taken no part in any rebellion, are murdered with virtually all of the leaders of Laois and Offaly by the English at a feast at Mullaghmast, County Kildare, in 1577. Rory Óg and his wife Maighréad O’Byrne, sister of Fiach MacHugh O’Byrne, are hunted down and killed soon afterwards. This leads to the political downfall of the O’Moore family as their estates are given to English settlers.

Given the causes of the rebellion and the Crown’s weakness during the Bishops’ Wars into 1641, O’Moore plans a bloodless coup to overthrow the English government in Ireland. With Connor Maguire, 2nd Baron of Enniskillen, he plans to seize Dublin Castle, which is held by a small garrison, on October 23, 1641. Allies in Ulster led by Sir Phelim O’Neill are to seize forts and towns there. The leaders are to assume the governing of their own country and with this provision offer allegiance to King Charles. They are betrayed, and the plan is discovered on October 22 and the rising fails in its first objective. O’Neill has some success, and O’Moore quickly succeeds in creating an alliance between the Ulster Gaelic clans and the Old English gentry in Leinster.

In November 1641, the Irish forces besiege Drogheda, and a royalist force comes north from Dublin to oppose them. O’Moore is one of the leaders of the rebel army that intercepts and defeats the relief force at the Battle of Julianstown on November 29.

In the ensuing Irish Confederate Wars, a major achievement by O’Moore is to recruit Owen Roe O’Neill from the Spanish service in 1642. He commands the Confederate forces in what is now County Laois and County Offaly, which remain peaceful, and helps arrange alliances with Murrough O’Brien, 1st Earl of Inchiquin, in 1647 and James Butler, 1st Duke of Ormond, in 1648. The resulting larger alliance fails to stop the Cromwellian invasion of Ireland (1649–53) in which an estimated third of the Irish population dies.

The Irish historian Charles Gavan Duffy writes: “Then a private gentleman, with no resources beyond his intellect and his courage, this Rory, when Ireland was weakened by defeat and confiscation, and guarded with a jealous care constantly increasing in strictness and severity, conceived the vast design of rescuing the country from England, and even accomplished it; for, in three years, England did not retain a city in Ireland but Dublin and Drogheda, and for eight years the land was possessed and the supreme authority exercised by the Confederation created by O’Moore. History contains no stricter instance of the influence of an individual mind.”

Bishop Michael Comerford writes that after O’Moore’s defeat at the Battle of Kilrush in April 1642 he retires and dies in Kilkenny city in the winter of 1642–43, having co-founded the Irish Catholic Confederation there a few months earlier. However, this ignores his contacts with Inchiquin and Ormonde in 1647–48.

In 1652, O’Moore goes to Inishbofin off the coast of Galway, one of the last Catholic strongholds, but as the parliamentary forces approach, he makes arrangements to flee. Walter Lynch, Bishop of Clonfert, sails in the last ship to leave the island without waiting for O’Moore, who is forced to make his own way. He finally escapes into Ulster but dies in obscurity on February 16, 1655. He is buried at Steryne churchyard, in the parish of Magilligan, County Londonderry.

St. Colman’s Church on the island once bears a tablet with the inscription: “In memory of many valiant Irishmen who were exiled to this Holy Island and in particular Rory O’More a brave chieftain of Leix, who after fighting for Faith and Fatherland, disguised as a fisherman escaped from his island to a place of safety. He died shortly afterwards, a martyr to his Religion and his County, about 1653. He was esteemed and loved by his countrymen, who celebrated his many deeds of valour and kindness in their songs and reverenced his memory, so that it was a common expression among them; ‘God and Our Lady be our help and Rory O’More’.”

O’More marries Jane Barnewall, daughter of Sir Patrick Barnewall, of Donabate, County Dublin, and his second wife Mary Bagenal. They had two sons and four daughters. His daughter Anne marries Patrick Sarsfield from an Old English Catholic family from The Pale. His grandsons include Patrick Sarsfield, 1st Earl of Lucan, who leads a Jacobite force in the Williamite War in Ireland, and his brother William Sarsfield, whose descendants include all the Earls of Lucan and the 4th and all subsequent Earls Spencer, through which O’More is an ancestor to Diana, Princess of Wales.

The Balyna estate is inherited from Calvagh O’More by Rory’s brother Lewis. Balyna is passed down to Lewis’s last surviving O’More descendant, Letitia, who is also descended from Rory O’More because her grandfather married a second cousin. Letitia marries a Richard Farrell in 1751. This Farrell family henceforth takes the surname More O’Ferrall.

The Rory O’More Bridge in Dublin is renamed after him. The film Rory O’More, made by the Kalem Company in 1911, directed by Sidney Olcott and Robert G. Vignola, sets O’More’s rebellion in 1798 rather than the 17th century, and moves the action to the Lakes of Killarney.