Verdon [Verdun], Theobald de, first Lord Verdon (1248?-1309), baron, was the youngest surviving son and heir of Sir John de Verdon, who had holdings in Buckinghamshire, Leicestershire, Wiltshire, Warwickshire, and Staffordshire, and of Margaret, daughter of Gilbert de Lacy (d. 1230), and granddaughter and coheir of Walter de Lacy (d. 1241), lord of Meath in Ireland, Weobley, Herefordshire, and Ewyas Lacy, Shropshire. Theobald's two elder brothers, Nicholas and John, were killed in Ireland in 1271, when Theobald was said to have been twenty-three years old, so that when his father died in 1274, he inherited a substantial estate stretching from the marches of Wales to Ireland. As a result of his inheritance, over the next thirty years, Verdon divided his time between England and Ireland and gradually became embroiled in the politics of these turbulent regions.

John de Verdon had strong ties to the crown, fighting for the royalists during the barons' wars, serving on behalf of the Lord Edward in 1261-3, going on crusade with Edward in 1270-72, and serving again in Ireland on his return, when his son Theobald acted as his attorney in England. After his father died, Theobald de Verdon continued this tradition of royal service. He was in Ireland after 1275 and was summoned to serve in Wales in 1277, 1282, and again in 1283. Verdon's men helped to transport victuals from Ireland to Wales to provision the royal army there in 1282. Verdon garnered some royal favours in these years. At his request, Nicholas de Netterville, his household knight in Ireland, was excused from royal administrative service in 1284. In that same year Verdon was granted special permission to receive his Irishmen into the king's peace, and also obtained the right to hold markets on a number of his Irish manors.

Verdon was summoned to parliament in 1275 and again in 1283, to discuss the capture of Dafydd ap Gruffudd. In 1290 he was among the magnates who granted an aid for the marriage of the king's daughter, and he was summoned regularly to parliament after 1295. In 1291 he and several other Irish lords graciously granted Edward a fifteenth of their moveables and of those of their men in Ireland.

Despite his loyal service Verdon later encountered problems with Edward I, beginning in Ireland. Henry III had seized Walter de Lacy's liberty of Meath, and some of those liberties had been restored to the coparceners of Lacy's estate, Geoffrey de Geneville and John de Verdon, Theobald's father. Geneville's liberties were more extensive than those assigned to John, and an inquest in 1266 stated that the Lord Edward would lose at least 400 marks a year if John's liberty was held as freely as Geneville's. When Verdon complained about his loss in 1279, another inquest was conducted upholding the earlier verdict, after which Edward seized all of Theobald's liberties in Meath.

At about that time Verdon was engaged in a long-running dispute with Llanthony Priory in the Welsh marches. The prior, who held a virgate of land of him, was summoned to Verdon's court to answer for a trespass. When the prior did not appear, Verdon's men seized cattle and other goods belonging to the prior, and refused to release them when the prior asked. The prior then brought a plea of trespass against Verdon accusing his men of a variety of misdeeds, including assault and homicide. Edward I intervened and ordered Verdon and his men not to vex the prior. But when the sheriff of Hereford and his men went to Verdon's court at Ewyas Lacy to investigate the matter, they were assaulted by Verdon's steward and a crowd of Welshmen, numbering 600 according to the aggrieved sheriff. The abbot of Combe similarly brought a plea of trespass in 1290 against Verdon, who in 1291 was swept up in the war between the earls of Gloucester and Hereford. In January 1291, along with other lords from the Anglo-Welsh marches, Verdon was summoned to testify about the conflict before royal justices. In March he duly appeared, and like the other lords refused to testify, claiming that the king's demand violated their liberties and the custom of the march. He similarly refused to allow his men to be impanelled as jurors.

Edward seized Verdon's lands to compel him to answer for his trespasses against Llanthony and his disobedience of royal orders. Having recovered his lands, in October 1291 he came before the king and council at Abergavenny, at the same time that the earls of Gloucester and Hereford were arraigned. Like them, Verdon was found guilty, and was ordered to appear before the king and council in parliament in January 1292 for judgment. Edward was at first harsh. Verdon was committed to gaol, and forever disinherited of his liberty of Ewyas Lacy. Yet Edward relented. On account of the good services that Verdon and his ancestors had performed for the king, and because Verdon had voluntarily confessed and submitted himself to judgment, Edward declared that his liberty would be restored to his heirs after his death, and that he would have to pay a fine of 500 marks. Ewyas Lacy was taken into royal custody on 19 February, but then restored to Verdon the following June.

Despite this punishment Verdon continued to come into conflict with his neighbours. In 1299 the prior of Llanthony once again complained about Verdon and his subjects in Ewyas, asserting that they were harassing the prior's men. Two years later Verdon's followers were similarly accused of committing trespasses against Sir John Hastings, so that the king had to warn him to amend his ways or be prepared to accept the remedy.

Although only in his forties, there are signs that Verdon may have been growing infirm during the 1290s. In 1295 he was summoned to parliament and ordered to help the justiciar of Ireland raise men to fight in Scotland. That same year he granted his eldest son, John, lands out of his patrimony without royal permission, and was fined accordingly. When in 1297 he was ordered to come to the king with horses and arms to fight in Gascony, he wrote back that he could not attend because of his infirmity, and because John, whom he had wanted to serve in his place, had died. Edward did not like the excuse and replied that he recalled that Verdon's second son, another Theobald, appeared fit, and so should be sent to serve in his father's place. Verdon stayed in Ireland in 1297 and 1298, and was discharged from service against the Scots in 1299. In March 1300 the Irish besieged him in Roch Castle. When the king summoned him for military service again in 1301, he stipulated that Verdon could send his son in his place if he was disabled by illness. He would then have been about fifty-three years old. Nevertheless, he attended the parliament at Lincoln in 1301, where he was one of the witnesses to the letter of the barons to the pope, and continued to be summoned for royal service in Scotland until his death in 1309.

Verdon married Margery, who brought land in Bisley, Gloucestershire, to the marriage. They had several sons: John, who died in Ireland in 1297; Theobald, who inherited his father's estate; and their younger brothers, Robert, Nicholas, and Michael. In April 1302 Verdon arranged a marriage between the younger Theobald and Matilda, daughter of Edmund (I) de Mortimer, in which both families promised lands in Ireland to the couple. They were married at Wigmore on 27 July. Theobald de Verdon the elder died at Alton, Staffordshire, the head of his patrimony, on 24 August 1309, when he was about sixty-one years old. He was buried with great honour among his ancestors in Croxden Abbey on 13 October.