Maguire, Conor (1616–45), 2nd baron of Enniskillen , was son of Sir Brian Maguire (qv); his mother was an O'Neill. His father ensured that the family was integrated socially within the new planter order. Conor married Mary, daughter of Thomas Fleming of Castle Fleming, King's Co. (Offaly); they had one son. To further this assimilation Sir Brian dispatched his son to Oxford, where he studied at Magdalen College but eventually failed to take his degree. On Sir Brian's death (1632), Conor succeeded to his estates and became 2nd baron of Enniskillen. He first attended the Irish house of lords on 16 March 1640.
Later, while attending the sessions in February 1641, Maguire was approached by Rory O'More (qv), who was trying to foment a catholic rebellion in Ireland while English attention was focused on Scotland. One of the major incentives that caused Maguire to listen so attentively to O'More's overtures was the extent of his own indebtedness. Another factor to consider was the fears held by many of the Irish catholic nobility concerning the intentions of the London parliament towards them and their faith. Together they gathered a group of plotters, but despite meetings no substantial progress had been made by August 1641. But the fumblings of Maguire and his fellow conspirators were abruptly dispelled after the arrival of Irish recruiting colonels for the Spanish army in May 1641. By August these colonels, allegedly with the support of Charles I, had hatched a plan to seize Dublin castle, and one of them approached Maguire, asking him to throw his lot in with them. Maguire kept this to himself till the ‘colonels’ plot’ had fallen through (September). At this point several of the colonels joined Maguire's party of plotters, and their infusion of military experience and planning steeled the plotters to action. At a meeting on 5 October 1641, the plan was finalised and 23 October was set as the date for the seizure of Dublin castle.
However, the council was alerted by Col. Hugh Og MacMahon's foolhardy and drunken disclosure of the plot to his foster-brother, Owen O'Connolly, on 22 October. The council acted quickly and decisively, capturing MacMahon after a struggle; later, after much searching, they found Maguire hiding in a cockloft not far from his lodging. Brought before the lords justices and council, he denied all knowledge of involvement in the plot, but admitted there were rumours. However, he recanted his denial, admitting his role on 23 March 1642, and made a full confession some six months later. In the meantime, he and MacMahon were transferred to England and lodged in the Tower of London before being removed to Newgate prison. In both institutions they were treated cruelly and were regularly denied food; so when their chance came to escape in August 1644, they grasped it. For six weeks they evaded their pursuers. After their recapture MacMahon was quickly hanged, but Maguire's status as a peer of the realm made his execution more problematic. In February 1645 Maguire was brought to trial before Sir Francis Bacon, justice of the king's bench, and was sentenced to suffer death by being hanged, drawn, and quartered at Tyburn. Before he was put to death, Maguire, clutching some papers, embraced his catholic faith, then submitted to the executioner, and died with great dignity.