O'More (Ó Mórdha), Rory (Ruaidhrí Caoch) (c.1515–1547), lord of Laois, was third son of Conall O'More (qv), lord of Laois, and his wife Gormflaith O'Carroll. He appears first in October 1537, when he was served with a subpoena to give evidence in a murder case in the king's court at Kilkenny. To the horror of the official who served the subpoena, Rory irreverently threw the writ in the mud and stood on it. When Conall died sometime shortly after June 1537, his brother Piers became lord of Laois with the support of Piers Ruadh Butler (qv), earl of Ossory. To appease and gain the support of the lord deputy, Leonard Grey (qv), Piers agreed to maintain some government gallowglass in Laois. Conall's sons, led by Laoiseach, the eldest and lord of Slemargy, refused to accept Piers's lordship and a dynastic war erupted in Laois late in 1537. Laoiseach was killed by the gallowglass before the close of 1537, but his brothers Céadach Ruadh and Rory carried on the war with Piers.
On 14 January 1538 Grey negotiated a peace between Rory and his elder brother Céadach Ruadh and Piers. Peace proved to be short-lived and Grey encouraged the brothers and other former Geraldine clients to attack Piers and the Carlow lands of Piers Ruadh. In June 1538 Piers complained to the local army commander at Athy, Co. Kildare. Rory suddenly arrived and attempted to kill his uncle in the presence of the commander, who was forced to arrest Piers for his own safety. Grey then convened a meeting in Dublin between Piers and his nephews, Céadach Ruadh and Rory. To Piers's dismay, Grey imprisoned him, paraded him in chains, and allowed Céadach Ruadh and Rory to return to Laois, where they resumed their attacks on the Butlers and their uncle's tenants. In August 1538, on his release, Piers renewed his submission and the king's commissioners confirmed his lordship of Laois. However, he was eventually exiled from Laois by his nephews.
In Piers's place Céadach Ruadh was inaugurated as lord of Laois. It is clear that substantial divisions subsequently emerged shortly afterwards among the brothers. Rory remained closely allied to Céadach Ruadh, while Giolla Pádraig entered into an alliance with Brian O'Connor Faly (qv), lord of Offaly, by marrying his daughter and attacked the Pale in the company of his new father-in-law and the O'Tooles in May 1540. In September 1540 the lord deputy, Anthony St Leger (qv), forced the submission of Céadach Ruadh and all his brothers. Céadach Ruadh and Rory adopted a conciliatory policy towards the Dublin government and attended the lord deputy on campaigns in Ulster and Munster. In 1541 Céadach Ruadh attended the parliament, and with his family was pardoned (27 June) and given a grant of English liberty (28 June).
During 1542 Rory, through election, became lord of Laois in succession to Céadach Ruadh, who was killed by Domhnall MacMurrough Kavanagh (qv) in Carlow. After his inauguration, Rory submitted before the council at Dublin on 13 May 1542. In an indenture of the same date, he promised military service to the government and concluded an agreement concerning the lordship of Slemargy with Robert St Leger, sub-constable of Carlow castle. On 10 November 1542 Rory again submitted before the council at Dublin and confirmed his concord with Robert St Leger. It seems that Rory inherited his father's mistrust of O'Connor Faly. He became convinced that his midland rival, who was favoured by Anthony St Leger, fanned his brother Giolla Pádraig's ambitions. This threat forced Rory to ally himself with James Butler (qv), 9th earl of Ormond. Between 1543 and 1544 he married Margaret Butler. This union greatly alarmed O'More's neighbour Brian MacGillapatrick (qv), baron of Upper Ossory, who sought an alliance with O'Connor Faly. From the evidence, O'Connor Faly encouraged the feud between Rory and his brother Giolla Pádraig, and incited MacGillapatrick to raid Rory's lands early in 1544.
In March 1546 St Leger returned to England to answer charges of misgovernment. Fearing the fall of his patron, O'Connor Faly and Giolla Pádraig attacked the Anglo-Irish settlements of Co. Kildare, for the first time in six years, in late 1546. The lord justice, Sir William Brabazon (qv), with Rory successfully crushed the rebellion. In the fighting, Rory killed O'Connor Faly's eldest son and forced Giolla Pádraig to flee into Offaly. St Leger returned to Ireland as lord deputy in December 1546, and made both Rory and Giolla Pádraig submit; the brothers were brought to Dublin to settle their dispute under his mediation. During Rory's detention in Dublin, O'Connor Faly devastated Laois and constructed forts there. When Rory attempted to return to Laois, St Leger forcibly detained him in Dublin. In a letter to Henry VIII, Rory accused St Leger of encouraging O'Connor Faly and Robert St Leger to attack his lands. During 1547 Rory faced another revolt led by Giolla Pádraig. Initially, Rory was successful and forced Giollá Padraig to flee; however, Giolla Pádraig returned with his O'Connor Faly allies, killed Rory in battle, and seized the lordship of Laois before summer 1547.
Although Rory's reign as lord of Laois was short, he did try to give his lordship some stability by developing good relations with the government and later with the Butlers. However, his demise was hastened by the continual interference of his powerful neighbour, O'Connor Faly. Rory left, by the daughter of Tadhg O'Dunne and by Margaret Butler, three recorded sons.