Preston, Jenico (Genico) (1585–1630), 5th Viscount Gormanston , landowner and champion of the catholic cause, was the son of Christopher Preston, 4th viscount, and his wife Catherine, daughter of Sir Thomas Fitzwilliam of Merrion, Dublin. Preston succeeded to his father's title in 1600, at which time he was reported to be receiving his education at the Irish college at Douai; he apparently gained livery of his estate on 16 June 1608. Despite his frequent complaints about his debts, he appears to have been one of the wealthiest landowners in the kingdom, his main estates being in Meath and Kildare. Much of this wealth was spent harbouring and maintaining catholic clergy, and he was regarded as the catholic church's most generous benefactor in Ireland. His staunch catholicism, combined with his wealth and political influence, meant that he was regarded with suspicion by the government, particularly as his brother Thomas Preston (qv) was a captain in the Spanish army in Flanders. Preston was one of the Roman catholic peers of Ireland who subscribed the declaration of James I's accession to the throne of England in 1603.
In October 1605 the lord deputy, Sir Arthur Chichester (qv), issued a royal proclamation banishing all catholic clergy from Ireland and ordering the catholic laity to attend Church of Ireland services. The catholic landowners of the Pale reacted by signing a petition in November, in which they called for toleration for their private practice of their religion and requested that the enforcement of the proclamation be suspended until they could apprise the king of their loyalty. Gormanston was one of the leading architects of this petition and, after it had been delivered to Chichester, went to the lord deputy to ask for his response. Chichester was offended at this presumptuousness and imprisoned him on 7 December. Gormanston and others then signed another petition declaring that Chichester's use of the prerogative court of castle chamber to fine and imprison recusants was unconstitutional. In January 1606 the English privy council advised the deputy to release the prisoners once they had entered bonds for their future appearance before him. This was apparently quickly accomplished, but the opposition to the ‘mandates’ remained steadfast, and Chichester was eventually forced to abandon his policy in 1607.
Gormanston became embroiled in further trouble when Sir Cahir O'Doherty (qv) rebelled in 1608. Having stood surety of 500 marks for O'Doherty, his brother-in-law, the previous year, Gormanston was accused of having encouraged the revolt and was called to appear before the Irish council. He successfully defended himself, but was obliged to pay 500 marks in default of O'Doherty's bonds. After disingenuously pleading poverty, he had this amount reduced to 200 marks and in the end may not even have paid that sum. In 1609 Christopher St Lawrence (qv), 9th Baron Howth, accused him of having been privy to an alleged conspiracy that was supposed to involve Sir Garret Moore (qv). Chichester did not believe the rather unreliable Howth, and Gormanston received a royal pardon, though this displeased him as he wished for the matter to come to trial so that he could clear his name and discredit Howth.
In November 1612, Chichester having summoned a meeting of the Irish parliament, Gormanston and four other catholic lords wrote to King James complaining that Chichester's procedure in calling the parliament was flawed and that they should have been consulted by the deputy in relation to any proposed legislation. In doing so they gave expression to the fears of the catholic community in Ireland that harsh new anti-catholic legislation was to be introduced in the parliament. Chichester's refusal to countenance such consultation heightened those fears, and shortly before the first session of the parliament in May 1613 eleven catholic lords, including Gormanston, complained about illegal practices in the election of some MPs, the erection of new corporations in order to elect protestants, and the denial of the franchise to some of the old boroughs which would have voted for catholic MPs. When they received no response, the catholic lords announced that they would boycott the house of lords. Such was the air of tension that, as parliament opened on Whit Sunday, 18 May, Gormanston and Viscount Buttevant (qv) almost came to blows in a dispute over which of them was the senior viscount; as the deputy made his way from Christ Church cathedral the two recusant viscounts, who had waited outside during the ceremony, vied for precedence in his train. The incident reached a climax when two of their followers apparently drew swords, whereupon the deputy called the guard. Meanwhile, the opening of parliament led to uproar and violence in the house of commons between catholic and protestant MPs, after which the catholics announced that they would not attend the session.
The catholics then sent two delegations to England to present their grievances to James in person; Gormanston was among the first group. The king agreed to establish a commission of inquiry to investigate their allegations, and the delegates returned to Ireland, Gormanston by 16 November. In January 1614 James summoned a delegation of catholic lords, including Gormanston, to attend on him. That April James dismissed most of their charges as trivial and berated them for their behaviour. However, in July he addressed the recusant delegation again and pledged to withdraw anti-catholic bills from the Irish parliament and to disallow the return of protestant MPs from some of the newly created boroughs, thereby sharply reducing the protestant majority in the house of commons. Having achieved some of their aims, the catholics returned to parliament for the sessions in 1614 and 1615.
In June 1615 Gormanston's eldest son, then aged about ten, was included among a list of the children of catholic lords and gentlemen who were to be educated in England, presumably with a view to converting them to protestantism. This plan was not implemented, though the privy council renewed the offer in 1618, when Gormanston again refused. In 1621 he, together with John Rochford, claimed a large part of Co. Leitrim on the basis of ownership by a distant ancestor. Their claim was rejected but to placate them the crown granted them the reversion to 1,600 acres in the county. Gormanston was again involved in proposals to send delegates to England in 1623. In 1626–7, after the outbreak of war with Spain, he was one of four lords of the Pale regularly consulted by the Irish administration about the raising of additional revenue for the defence of Ireland in return for royal concessions. It was their absolute refusal to cooperate that led first to the convention of a ‘great assembly’ in Dublin in April 1627, which endorsed their stance, and later to the transfer of the negotiations to London that led to Charles I's grant of the ‘graces’ in May 1628 in return for subsidies amounting to £120,000 sterling.
Gormanston married, while a minor, Margaret, daughter of Nicholas St Lawrence, Baron Howth, with whom he had three sons, Nicholas, who succeeded as sixth viscount, Robert, and Thomas, and five daughters, Mary, Elizabeth, Jane, Catharine, and Margaret. His will was dated 2 November 1629, and he apparently died 14 March 1630.