Lowther came from an old and distinguished family with an impressive record of parliamentary service for Cumberland and Westmorland, dating back to the beginning of the fourteenth century. His eldest brother Robert sat in at least seven Parliaments between 1391 and 1417; and their sibling, William, did so twice. These two occupied a dominant position in the north-west for most of the first decade of the fifteenth century, all but monopolizing the principal offices of local government in their region.
An important factor prompting Lowther to move south was his service to Thomas Neville, Lord Furnival. The resignation of his forestership in March 1401 coincided with his appearance in the Exchequer as surety for that lord, and his description as ‘of Yorkshire’ suggests that he was a member of Furnival’s household. The association was born of the Lowthers longstanding connexion with the great northern family of Neville, for Geoffrey’s brother Sir Robert was a trustee of the estates in Cumberland of Furnival’s elder brother, Ralph, earl of Westmorland, and was to be made an executor of the earl’s will.
After Henry V acceded to the throne Lowther successfully petitioned for a confirmation of his annuity and duchy office, and on 18 June 1414 he received a new annuity, of the larger sum of 25 marks, from the issues of Staincross.
Within two years of Duke Humphrey’s appointment as warden of the Cinque Ports and constable of Dover castle in November 1415, he promoted Lowther to be his lieutenant, an important office which he was to fill until late in the 1430s. He continued to act in a legal capacity for the duke, being named as a feoffee again for lands in Pembrokeshire and on the Isle of Wight in July 1418,
By then, owing to his position as Gloucester’s lieutenant warden of the Cinque Ports, Lowther had emerged as a man of great importance within Kent, well qualified for election to Parliament. He had been appointed a j.p. in the county and had developed strong relationships with other members of the county elite. The most significant of these was the ones he had established with other northerners who had shared his early links with the Nevilles, chief among them John Darell, who had been Lord Furnival’s under treasurer in the Exchequer and was to be named, with Lowther’s brother, as an executor of the earl of Westmorland,
The premature death of Henry V in August 1422, leaving as his heir a mere infant aged nine months, presented his brothers the dukes of Bedford and Gloucester with the problem of establishing governments in France and England during a prolonged minority. While Bedford remained in France as Regent, Gloucester’s role at home needed to be defined, and more particularly a Parliament had to be summoned to decide the power and title to be accorded to whichever of the royal uncles was to assume authority until the King came of age. It is not surprising that Gloucester’s lieutenant warden, Lowther, was elected one of the knights of the shire for Kent in the Commons summoned to meet on 9 Nov. The circumstances of his election are obscure, but his friend, John Darell, made the return as sheriff, and the fact that the indenture was attested by only a dozen men suggests that it was not contested.
Lowther was not to be elected to the Commons again for three years, but his friendship with Darell led to him attesting Darell’s election to the Parliament of 1425,
A measure of Lowther’s importance is his summons in April 1434 to the great council which met to discuss Gloucester’s attack on the conduct of the war in France by his brother, the duke of Bedford. Both Gloucester’s highly critical memorandum, in which he had offered to lead an army to France himself, and Bedford’s reply were taken by the protagonists to be personal slights to their honour, and the composition of the great council reflected the regime’s desire to lessen tensions. As well as lords spiritual and temporal, it included men aligned with the two dukes: thus Lowther was joined by fellow Gloucester servants, such as William Haute and John Tyrell, and Bedford’s men were represented by Lewis John*, Richard Buckland* and Richard Wydeville*. Ultimately, however, the proceedings ended in a rebuff for Duke Humphrey. On 5 May those present petitioned the King stating that they had rejected Gloucester’s offer to lead an army to France only because of the impossibility of raising the £48,000-£50,000 they had calculated it would cost. Instead they asked that the ‘people of your land be called in forme accustumed for þis matere’ (that is, that a Parliament be summoned) and that they ‘be not noted of eny default of non execucion’ of Gloucester’s offer.
Meanwhile, in the spring of 1434 Lowther had headed the list of men of Kent who subscribed to the oath not to maintain peace-breakers, and he long continued to be active in Kentish affairs.
In the late 1430s the pace of Lowther’s activities slowed down, perhaps as a consequence of ill-health, and indeed he must have been quite old by this date. In December 1437, after Henry VI attained his majority, he was required to surrender his offices of receiver- and attorney-general of the duchy of Lancaster. Although he remained active on ad hoc commissions in Kent, and appears to have continued to attend sessions of the peace regularly until his death,
The date of Lowther’s death is not known but a writ of diem clausit extremum was sent to the escheator of Kent on 1 July 1445,
