Mayart, Sir Samuel (1587–c.1647), lawyer, was the son of Gilbert Mayart of Ipswich, Suffolk, England, who was of Flemish origin. He matriculated at Merton College, Oxford, in May 1604, at the age of 17, and was admitted to the Middle Temple in 1607, called to the bar in 1614, and confirmed in February 1616. Two months later, he was admitted to the King's Inns in Dublin, when he was described as an attorney. In November 1624, some two weeks after the death of the second justice of the common pleas, Sir Gerard Lowther (qv), a correspondent informed the English secretary of state, Lord Conway, that Mayart was prepared to offer £300 for the office: since it was worth only £100 a year, he thought there should be ‘no great difficulty’ in procuring it. A patent was issued in January 1626 but Mayart's fitness for the place was questioned. His learning and integrity were vouched for in June 1625 by Richard Bolton (qv), attorney of the court of wards, and his son Edward (qv), solicitor general, and Mayart was finally appointed in July.
Mayart, who was knighted by the lords justices in 1631 and elected treasurer of the King's Inns in 1633, subsequently served as a master in chancery and as a judge of assize on the north-eastern circuit and was in attendance on the house of lords during the parliaments that met in 1634 and 1640. He was one of two dissenting judges in the ‘case of tenures’ in 1637. In November 1639 he was appointed to a commission to report on the celebrated Weston case, which was one element in the campaign by Lord Deputy Wentworth (qv) to discredit the conduct of business by the lord chancellor, Adam Loftus (qv) in the court of chancery. In August 1641 the Irish administration recommended that Mayart should receive arrears in full compensation for a salary reduction in 1629.
In April 1644, in his capacity as an officer of the lords' house, he became involved in the debate which arose from the circulation in manuscript of a work entitled ‘A declaration how, and by what means, the laws and statutes of England, from time to time, came to be of force in Ireland’. The anonymous author argued the case for the independence of the Irish parliament, maintaining that Ireland had been governed ‘according to the model of England’ since the reign of King John (qv) and that the English parliament had no more claim to jurisdiction in Ireland than it had in Scotland. The ‘declaration’ was brought to the attention of the lords on 10 April, and in the course of the following week it was agreed that it should be considered by a joint committee, composed of the commoners ‘of the long robe’ and the judges in attendance on the lords, and that a report should be given at the next session.
The issue was both sensitive and contentious. Less than two years previously the lords had denounced a proposed bill as ‘prejudicial to this kingdom, by admitting the parliament of England to be of force, to oblige us here, without being confirmed’ (Journals of the house of lords [Ireland], i, 183). The committee never presented its report, but Mayart, who had been the principal intermediary between the houses, subsequently published an Answer to a book entitled a declaration in which he vigorously rebutted the case for Irish legislative independence. From the premise that Ireland had been acquired by conquest, unlike Scotland, but like Wales, he concluded that Ireland ‘was and is a member of England united to it, and as a part or province of England governed’ and equated Irish parliamentary enactments with the by-laws of cities and corporations.
Mayart was last recorded, in attendance on the lords, on 24 February 1646 and is presumed to have died shortly afterwards. He was married three times, but only the identity of his second wife, Mary Smith, widow of Primate Henry Ussher (qv) (d. 1613), is known.