O'More (Ó Mórdha), Rory (Ruaidhrí Óg) (c.1544–1578), lord of Laois, was second of three recorded sons of a Rory O'More (qv) (d. 1547), lord of Laois, and the daughter of Tadhg O'Dunne, and was one of the most prominent Irish leaders of Leinster between the late 1560s and his death. After the killing of his father by the troops of his uncle Giolla Pádraig Ó More early in 1547, it seems Rory and his half brothers were removed from Laois by his father's second wife, Margaret Butler. Virtually nothing is known of Rory's upbringing and education. It is distinctly possible that he and his brother were either brought up in the lands of the Butlers or within the Pale. Later his half-brother, An Calbhach, entered Gray's Inn, London, during 1567.
Rory, unlike his half-brothers, seemingly returned to Laois early in the 1560s. The young O'More quickly found a friend and a patron in the person of Sir Francis Cosby (qv), sheriff of Laois since 1564. They combined to cultivate a lucrative income from extortion of black rents from both planter and Irish rivals. Since the death of Rory's father, the political constitution of Laois had profoundly changed. Planters and government garrisons were established in Laois during the years that followed the defeat of Rory's uncle Giolla Pádraig and his ally Brian O'Connor Faly (qv), lord of Offaly, in 1548. The rough justice meted out to O'More leaders by government officials and planter grandees made Laois a land fraught with continual violence. In 1557 Conall Óg, lord of Laois and another of Rory's uncles, was crucified at Leighlinbridge, and Domhnall son of Laoiseach O'More, a cousin and lord of Slemargy, was hanged. In the parliament of 1557–8, legal effect was given to the plantation of Laois and Offaly by the creation of two shires. This contributed to a rebellion of the O'Mores and O'Connor Falys in 1558. During the early 1560s Rory's cousin Céadach mac Conaill led a campaign of resistance to the planters, while other cousins such as Muircheartach son of Laoiseach, now lord of Slemargy, and Laoiseach son of Céadach Ruadh benefited from the plantation and lent it military support. What effect this had on Rory cannot be discerned, as his alliance with Cosby saved him from the worst rigours of the plantations.
However, the planters overstepped the mark when they hanged two cousins allied to Rory in the middle of the 1560s. This act greatly embittered O'More, and his friendship with Cosby began to cool. Symptomatic of his disillusion were his increasing contacts with Aodh O'Byrne (qv), lord of the Wicklow mountain lordship of Crioch Raghnuill. From the middle of the 1550s O'Byrne, from the safety of his Glenmalure stronghold, had maintained Irish dissidents throughout Leinster, particularly in Laois and Offaly, and was eager to increase his family's status and influence throughout the province by military aggression and marriage. The young emerging O'More warlord was a perfect vehicle for O'Byrne ambitions. The first visible signs of Rory's discontent are manifested in his pardon of 17 February 1566, which coincided with a grant of a commission to Gerald Fitzgerald (qv), 11th earl of Kildare, to make war upon the O'Mores in March 1566. Rory seems to have remained at peace for the remainder of the 1560s. In 1570 the government's execution of the hitherto loyal Laoiseach son of Céadach Ruadh at Leighlinbridge, for conspiracy, left Rory as the principal O'More leader, with the exception of Muirchartach son of Laoiseach, lord of Slemargy.
By April 1571 Rory was openly disaffected. He rebelled with Fiach O'Byrne (qv), Hugh's eldest son and heir, and caused considerable damage to the Pale. Fiach was implicated with his brother-in-law Brian (qv) son of Cathaoir Kavanagh (qv) in the murder of Robert Browne on 21 April 1572. This resulted in the destabilisation of east Leinster. In August 1572, with the queen's approval, Sir Nicholas White (qv), seneschal of Wexford and Browne's father-in-law, launched ferocious attacks on Fiach and Brian. Those accused with Rory coordinated their attacks to reduce much of the province of Leinster to chaos. Rory submitted in 26 August 1572, and was pardoned (September). His reformed ways did not last long. In the winter of 1572–3 he renewed his support of Brian and Fiach. During July 1573 trouble emerged in Laois; Kildare was granted a commission to make war on Rory and his O'Connor Faly allies. Sometime in November 1573 Rory cemented his alliance with the O'Byrnes by his marriage to Mairghréag, daughter of Aodh and favourite sister of Fiach. In January 1574 the intrigues of Gerald Fitzgerald (qv), 15th earl of Desmond, caused government officials to suspect Rory and the O'Byrnes of being Desmond's hopes for rebellion in Leinster. Earlier, Rory had helped Desmond escape from Dublin back to Munster in late 1573. These suspicions were confirmed by the coordinated attacks of O'More and Fiach upon the Pale during March 1574. In 1575 Kildare, the government's commander in the south and west regions of the Pale, was arrested and charged with conspiring with Rory and his O'Byrne allies to create turmoil within Leinster, which, it was alleged, would force the queen to make him lord deputy. Nothing was proved, and Kildare was allowed to return to Ireland in 1577. The harsh imposition of martial law in Laois by his now mortal enemy Cosby, seneschal of Laois since 1572, sparked Rory again into rebellion in 1576. He drew considerable support from dispossessed O'Connor Faly dynasts and devastated large tracts of the midlands and Meath.
In June 1576 he was received into the queen's peace by the lord deputy, Henry Sidney (qv), who hoped to accommodate Rory within the plantation of Laois. Rory acceded to Sidney's plan, but Cosby continued to harass his followers and lands. Inevitably, Rory was forced into war and Cosby was commissioned on 18 March 1577 to follow Rory with fire and sword. According to Thady Dowling's (qv) annals, Muirchertach son of Laoiseach, lord of Slemargy, allegedly allied with Rory. Muirchartach was murdered at a parley in Mullaghmast by Cosby and Robert Harpole, sheriff of Carlow. Gaelic Leinster was shocked by the murder; Rory responded quickly by burning Naas (May), and captured Sir Henry Harrington and Alexander Cosby (November). The planters rescued both men in a successful assault on Rory's camp. However, in the fighting Rory's wife was beheaded and two of his young sons were slaughtered. Although Rory was seriously wounded, he maimed Harrington before escaping into the night. Early in 1578, when he had recovered, Rory revenged his dead wife and children by devastating the Anglo-Irish towns of Co. Carlow and Co. Kildare, killing regardless of age or sex. After one of these raids he was compelled to take refuge in the O'Byrne heartland of Glenmalure from the government forces of Sir Nicholas Bagenal (qv). In July 1578 he was killed by the troops of Barnaby Fitzpatrick (qv), the loyalist baron of Upper Ossory. Although Rory's followers managed to bury his body, it was exhumed and decapitated. The head was sent to Dublin, where it was publicly displayed on the walls of Dublin castle.
Through his military ability Rory proved the largest obstacle to the advance of Elizabethan government in the midlands during the 1570s. His death left the Irish dissidents there leaderless, and directly faciliated the rise of Fiach O'Byrne to the leadership of the Leinstermen. In the short term his demise relieved government officials, but left them fearful of the revenge O'Byrne swore to take. Rory was succeeded as lord of Laois by his cousin, James son of Laoiseach. By an unknown first wife, Rory had four recorded sons. However, Uaithne (qv) and his sister Doireann were the issue of Rory's marriage to Mairghréag O'Byrne. Both children were brought up in Glenmalure under the protection of Fiach. Rory's career stands in stark contrast to that of his loyalist half-brother An Calbhach, who received grants of land in Meath and Dublin and died at a great age in 1618.