Fitzmaurice, Thomas (d. 1590), 16th baron of Kerry and Lixnaw , landowner and rebel, was the fourth and youngest son of Edmund Fitzmaurice, 10th baron of Kerry and Lixnaw, and his wife Una, daughter of Teige MacMahon of Thomond. Having three older brothers, he left Ireland and was trained as a soldier at Milan, where he settled, and served in the imperial army. With the death in 1550 of his brother Gerald, the 15th baron, Thomas inherited the title; he returned home in 1551 to find a usurper, variously named as either Gerald Fitzmaurice or John Fitzrichard, in possession of his lands. After a two-year dispute, the latter dropped his claim in 1552 and Queen Mary recognised Thomas as baron of Kerry and Lixnaw in October 1553. Soon after his return, Fitzmaurice married Margaret Fitzgerald, daughter of James Fitzgerald (qv), 14th earl of Desmond. Described as a handsome man, Fitzmaurice remained vigorous into old age. He enjoyed the high life, and the Gaelic annals laud him for his excellent taste in, and assiduous collection of, wine, horses, and books. English sources, however, indicate that he could not write. His main seat was at Lixnaw.
The barons of Lixnaw were reluctant vassals of the earls of Desmond, and Fitzmaurice spent most of his career in conflict with Gerald Fitzgerald (qv), 15th earl of Desmond from 1558. In 1560 Desmond invaded Fitzmaurice's lands, and sporadic violence persisted for the next two decades. Eager to undermine Desmond's power, the government favoured Fitzmaurice and pressed Desmond to respect his independence. In October 1567 Fitzmaurice's eldest son, Patrick (qv), accompanied the lord deputy, Sir Henry Sidney (qv), to London to petition that his father be permitted to hold his lands directly from the queen in return for an annual rent. Nothing came of this and in 1569 the crown briefly supported the claim of Sir Peter Carew (qv) to lands in Munster, including Fitzmaurice's lordship.
Desmond spent much of 1562–73 detained by the government in either Dublin or London, and Fitzmaurice capitalised on his absence by refusing to pay rent to the earl. Desmond's deputy James fitz Maurice Fitzgerald (qv) responded in July 1568 by plundering Thomas's lands and besieging him in Lixnaw castle. Short of supplies and with no help at hand, Fitzmaurice attacked the besiegers and won a great victory. Undaunted, Fitzgerald launched a rebellion against the crown in summer 1569. This revolt persisted until February 1573, during which time Fitzmaurice and his followers withstood further Fitzgerald raids and assisted the crown in various campaigns, including the relief of Dingle in August 1571 and the siege of Castlemaine in 1572.
Desmond's return to Munster in late 1573 threatened Fitzmaurice's hard-earned autonomy. During 1574 Desmond compelled him to hand over his sons as hostages and to promise military support. Fitzmaurice kept government officials abreast of Desmond's actions and appealed for help. None was forthcoming. On 30 August 1575 the royal commissioners for Munster agreed with Desmond's claims that Fitzmaurice's lands were subject to Desmond's private law court at Tralee and that he owed rents to Desmond. He remained defiant and there was fighting in 1576–7; Desmond had the best of it, seizing Ballmacqueem castle, besieging Lixnaw, and killing many of Fitzmaurice's tenants and followers. The government demonstrated its sympathies by granting former monastic lands held by Fitzmaurice to Desmond in 1578.
In autumn 1579 Desmond, who still had Fitzmaurice's sons as hostages, dragged him into joining a rebellion, but by mid-December Fitzmaurice had secured his sons’ release and immediately sought a royal pardon, submitting to the government in late February 1580. However, rather than help the crown to quell the revolt, he tried to remain neutral between the opposing sides and refused to give up his sons again as hostages. Desmond and his supporters spent much of summer 1580 in or near Fitzmaurice's lordship, but he made no attempt to apprehend them and indeed appears to have aided them. His formerly staunch loyalism had been shaken by the manner in which the government had sacrificed him in the 1570s to appease Desmond. Moreover, many believed that the crown would pardon Desmond and restore him to his former power. Exasperated royal officials kidnapped Patrick and Edmund Fitzmaurice in early August, and imprisoned them in Limerick.
In September 1580 Fitzmaurice alerted the government to the landing of papal troops near Dingle, and he met the lord deputy, Arthur Grey (qv), at Dublin on 12 September 1581. However, his relations with the government deteriorated in late 1581 when a royal garrison was established in his lordship at Ardfert. Inadequately supplied, these troops seized goods and livestock from local people, causing considerable distress as famine conditions then prevailed in Munster. Fitzmaurice's balancing act became impossible to sustain after his sons, who had escaped from Limerick in August 1581, attacked Ardfert at the start of May and killed the garrison's captain. Fearing that he would be blamed and possibly encouraged by reports of Spanish ships off the coast of Munster, Thomas joined his sons in rebellion.
After destroying four of his castles, he combined with Desmond and following a successful skirmish forced the government to withdraw from Ardfert in August. Thereafter, the crown forces regrouped and waged a relentless attritional war against Fitzmaurice, eventually forcing his submission to the royal general, Thomas Butler (qv), 10th earl of Ormond, at Clonmel on 5 April 1583. Ormond was an old ally of Fitzmaurice and, recognising that he had been pushed into revolt by the excesses of the royal soldiers, appealed to London on his behalf. Fitzmaurice received a formal pardon for himself, his sons, and his followers on 22 April 1585. During his final years he lived in poverty, estranged from the government owing to the settling of English colonists near his lands and the continuing imprisonment of his son and heir, Patrick.
He died 16 December 1590 at Clanmaurice, Co. Kerry, and was buried at Ardfert cathedral, after permission was refused to inter him in his family plot at Ardfert friary, then occupied by a royal garrison. His first wife was probably the mother of his four sons, Patrick, Edmund, Robert, and Richard, and a daughter Joan. After her death in 1563 or 1564, he married Catharine, daughter of Teige MacCarthy Mor, who died in 1582, and then Penelope (Finola) O'Brien, daughter of Sir Donal O'Brien of Thomond.