Maguire (Mág Uidhir), Pilib (Philip) (d. 1394), king of Fir Manach, eldest son of Aodh Ruadh Maguire (qv), king of Fir Manach, was a distinguished warrior and patron of poets whose fame was well known throughout Ireland and Scotland. Nothing is known of his mother. Pilib ‘of the battle axe’ is first mentioned in the annalistic record at his killing of Muircheartach O'Neill (3 March 1356). Seemingly the sept of the O'Neills that Muircheartach represented was intent on expanding their influence into the Maguire sphere. On the death of his father (1363), Pilib succeeded him as king. He was to prove an ambitious king, determined to expand his power at the expense of his neighbours. To the south he reduced the threat of the Clann Muircheartach Muimhnech O'Connors by treacherously killing their leaders in their own assembly (1366). In these years he also married Dubchablach, daughter of Pilib O'Reilly (qv), king of east Bréifne. When O'Reilly was deposed by his cousins from his kingship in 1369, Maguire placed a fleet on Loch Oughter and intimidated his father-in-law's captors to such an extent that they freed him. Earlier in that year, Pilib's northern border with the O'Donnells became disturbed. The sons of Niall O'Donnell captured Pilib's client Domhnall Ó Máeladuin, king of Lurg, and killed him. In reprisal, Pilib routed the O'Donnell fleet on Loch Finn. Pilib's expansion continued, but this time in alliance with Ó Fergail, O'Reilly, and O'Connor. During 1370 this confederation expelled their common enemy, the Clann Muircheartach Muimhnech O'Connors, from Muintir Eolais (Leitrim). By the close of the decade, he was interfering in the dynastic politics of the O'Neills. In 1379 Pilib and Domhnall O'Neill killed Richard Mac Cathamail, but were defeated in battle by Niall Mór O'Neill (qv) on 31 May 1379. After that Pilib's power may have declined, as the next reference to him is the notice of his death almost fifteen years later (16 March 1394).
Pilib was succeeded by his son, Tomás Mór Maguire (Mág Uidhir) (d. 1430). One of Tomás Mór's first actions was to move against the increasing threats posed by rival kinsmen. In 1395 the sons of Art Maguire captured Domhnall Ó Máeladuin, king of Lurg, and delivered him as a hostage to O'Donnell (qv). Perhaps in response, Tomás Mór captured his cousins Conchobhar Ruadh and Tomás, the sons of Aodh Ruadh Maguire. This firm approach to his vassals is further evidenced by his killing of Donnchadh Mac Cathamail (1404). His problems, however, continued with O'Donnell, who captured some of his kinsmen during 1407, and it took firm pledges from Maguire and his ally, O'Neill, to obtain their release. This growing relationship with O'Neill is revealed further when Aodh O'Neill and a son of Tomás Mór escaped together from Dublin castle (1412).
But it was increasingly clear that Tomás Mór was in decline. During 1418 his son Tomás Óg (qv) was captured by his first cousin Seaán Maguire with the aid of Brian Óg O'Neill. Later, during the harvest of 1421, Tomás Mór's sons were defeated by their cousins yet again. This weakness was exploited again by Niall Garbh O'Donnell (qv), who forced the submission of Maguire the next year and made him accompany him on campaign in Connacht. However, the pilgrimage of Aodh Maguire, Tomás Mór's cousin and rival, to Compostella allowed him to wrest back the advantage within Fir Manach. In his absence, Tomás Mór and his sons seized Aodh's castle and lands before expelling his followers from Fir Manach, thus repairing their inroads into Maguire's power. On 13 November 1430 Tomás Mór (described as ‘man of hospitality and prowess’) died after a reign of thirty–six years.