JENKINS, Sir LEOLINE (1623-1685), civilian and diplomatist, son of Lewellyn or Leoline Jenkins, a gentleman of moderate estate at Llanblethian, Glamorganshire, was born at Llantrissant in that county in 1623. He received his early education at the grammar school of Cowbridge in his native county, whence he proceeded in 1641 to Jesus College, Oxford. On the outbreak of the civil war he left Oxford and served for a time in the royalist army in Wales. In 1648 he joined the ejected head of his college, Dr. Francis Mansell [q. v.], at the house of Sir John Aubrey at Llantrithyd, where he acted as tutor to Aubrey's eldest son. In May 1651 he was indicted 'for a seminary of rebellion and sedition,' and returned with his charge to Oxford, where he took pupils in a house in the High Street, which in consequence came to be known as the Little Welsh Hall. In June 1655 he anticipated a threatened 'bannition' by the parliament by retiring to the continent with his pupils, and spent the next three years in travel in France, Holland, and Germany (Reg. of Visitors to the Univ. of Oxford, Camden Soc.; Jenkins, Life of Francis Mansell, D.D., 1854, pp. 19-20, 26). On his return to England he resided for a time in the house of Sir William Whitmore, bart., at Apley, Shropshire, but returned to Oxford on the Restoration, was elected a fellow of his college, and on 16 Feb. 1660-1 took the degree of LL.D. On Dr. Mansell's resignation (1 March 1660-1) he succeeded him as head of the college, and discharged the office with ability. His friend Sir William Whitmore gave him the commissaryship of the deanery of the peculiar of Bridgnorth, Shropshire. The Dean of Westminster (John Earles) appointed him registrar of the consistory court of the abbey. In 1662 he was appointed deputy-professor of civil law in the university, and he was also assessor to the chancellor's court. He had long been a friend of Sheldon, whom he helped in the foundation of his theatre, drawing the conveyance with his own hand; and on Sheldon's translation from the see of London to that of Canterbury, he became his commissary and official for that diocese, and probably his vicar or official-general. He was also accustomed to conduct the foreign correspondence of the university, and was appointed to receive foreign visitors of distinction.
On 11 Nov. 1664 he entered the College of Advocates, and soon afterwards was appointed deputy to Dr. (afterwards Sir) Giles Sweit in the court of arches. On the outbreak of the Dutch war Jenkins was selected by the commissioners of prizes to serve on a committee entrusted with the framing of rules for the decision of prize cases (6 Feb. 1664-5). On 21 March following he was appointed assistant to Dr. John Exton [q. v.], judge of the court of admiralty. On the death of Exton he succeeded to his office, and on the death of Sir William Mericke, judge of the prerogative court of Canterbury, in January 1668-9, he succeeded to his place also. The death of Henrietta Maria at Colombes, near Paris, in the following August, raised an important point of international law. By English law Charles II was entitled to succeed to her personal property as her next of kin, to the exclusion of every one else, the statute of distributions not having then been passed. On the other hand the succession was claimed by Henrietta, duchess of Orleans, on the ground that she was the only one of Charles I's children who was entitled to succeed by French law. The English case was stated by Jenkins, who rested it on the somewhat questionable ground that as a member of the royal household Henrietta Maria could not by her residence in France divest herself of the English domicile which she had acquired on her marriage. Jenkins was also sent to France to assist the English ambassador in recovering the disputed succession. There his arguments or considerations of policy prevailed, and the Duchess of Orleans's claim was set aside. On his return he was knighted, 7 Jan. 1669-70 (Pepys, Diary, 26 March 1667; Cal. State Papers, Dom. 1664-5, p. 427; Strickland, Queens of England, ed. 1845, viii. 264). Jenkins was one of the commissioners in the abortive negotiations for a union with Scotland which took place in the autumn of 1670. From a letter to the Duke of York, written by him during the negotiations, it appears that he was adverse to the project (Mackenzie, Memoirs of the Affairs of Scotland from the Restoration of King Charles II (1821), p. 203). In 1672 Jenkins became one of the managers of the university press. On 11 Feb. 1672-3 he was returned to parliament for Hythe (Letters of Humphrey Prideaux to John Ellis, Camd. Soc., pp. 74-9), and in the following April resigned the headship of Jesus College. Sunderland, who did not act under the commission, Jenkins, and Sir Joseph Williamson [q. v.] were appointed to represent England at the abortive congress which, by the suggestion of Sweden, was summoned at Cologne (5 May 1673) to mediate between Holland on the one part and France and England on the other. Jenkins and Williamson returned in May 1674 to London, where a separate peace had already been concluded between England and Holland (19 Feb. N.S.) On his voyage home, while still in the Meuse off Brielle, Jenkins fired on a Dutch man-of-war for neglecting to lower her flag, upon which the Dutchman obeyed under protest (Mignet, Négociations relatifs à la Succession d'Espagne, iv. 138 et seq.)
The congress of Cologne was followed in 1676 by that of Nymwegen, at which Jenkins again represented his sovereign. Jenkins's colleagues were Lord Berkeley of Stratton [see Berkeley, John first Lord Berkeley of Stratton] and Sir William Temple [q. v.], but the burden of the negotiations fell upon him. He left England on 20 Dec. 1675, and reached the Hague on 3 Jan. (N.S.) Passing Brielle he fell in with two Dutch men-of-war, which saluted him only with their guns, but lowered their pennants on receiving the fire of his yacht. He reached Nymwegen on 16 Jan. (N.S.) Negotiations had hardly begun when Temple was recalled in June 1677, and nothing was done at Nymwegen until after the marriage between the Prince of Orange and the Princess Mary of England (4 Nov.) and the conclusion of an Anglo-Dutch alliance (March 1678, N.S.) In Temple's absence Jenkins showed much discretion in his relations with the French envoys, although he was unable to accept their terms. Louis, however, by his dilatory diplomacy and activity in the field, succeeded in avoiding a general treaty, and opened negotiations with Holland for a separate peace, which after much higgling was signed on 10 Aug. It was followed by a treaty with Spain on 7 Sept. (N.S.), and another between France, Sweden, and the Empire on 5 Feb. 1679 (N.S.). The latter treaty Jenkins and Temple refused to sign, because the imperial ambassadors would not accord them the precedence due to their position of mediators. They accordingly withdrew from the congress, and Jenkins was accredited resident ambassador to the States General (14 Feb.). On 20 Feb. a new commission was issued appointing him sole representative of his sovereign at the congress, and on 26 March (N.S.) he returned to Nymwegen. Denmark and Brandenburg still retained their Swedish conquests, and there were commercial disputes between Sweden and Holland. Jenkins was to mediate the best arrangements he could between all parties. After negotiations had begun the French, by a timely invasion of the duchy of Cleves, compelled Brandenburg to restore the disputed territory to Sweden (29 June, N.S.). A French army had already invaded Oldenburg and Delmenhorst with the view of settling the Danish question in a similar way, when Jenkins was recalled (11 July), and the congress broke up. Before leaving Nymwegen Jenkins marked his resentment at the bad faith displayed by Louis during the negotiations by rejecting a present of his miniature set in diamonds, though Colbert urged its acceptance to the point of importunity. He reached London about the middle of August, was graciously received by Charles, and was forthwith returned to parliament for the university of Oxford, which he continued to represent during the rest of his life.
Jenkins was sworn of the privy council on 11 Feb. 1679-80, and succeeded Henry Coventry (1619-1686) [q. v.] as secretary of state on 26 April. In this capacity he led the opposition to the bills for excluding the Duke of York from the succession and to Sir John Hotham's motion for printing the votes and proceedings of the House of Commons, 24 March 1680-1. Being ordered by the house to impeach Edward Fitzharris [q. v.], the supposed author of a pamphlet libelling Charles as a papist, he at first refused, considering that the impeachment was intended merely as an affront to the king, but after an angry debate submitted. The impeachment was dismissed on the technical ground, long since overruled, that none but peers were impeachable. Jenkins was one of the principal witnesses against the Earl of Shaftesbury in his trial at the Old Bailey on 24 Nov. 1681 [see Cooper, Anthony Ashley, first Earl of Shaftesbury, (1621-1683); and Luttrell, Relation of State Affairs, i. 146]. He managed the return of the court nominees at the election of sheriffs in 1682. He disapproved, however, of the proceedings by quo warranto which followed. He resigned the seals on 4 April 1684, receiving a bounty of 5,000l., and retired in broken health to his house at Hammersmith, where he died unmarried on 1 Sept. 1685. He was buried in the chapel of Jesus College, Oxford, to which he had been a munificent benefactor. During his lifetime he had contributed liberally to its enlargement, and by his will he endowed it with the bulk of his property. He left some of his manuscripts to All Souls' College, Oxford (Coxe, Cat. of MSS. in the possession of the Colleges and Halls of Oxford); these include among others a copy of his will, and miscellaneous papers drawn up when secretary of state and while at Nymwegen. An index, also preserved at All Souls', was made by Dr. Owen Wynne.
Jenkins lacked resource and independence of mind, was a great stickler for forms, and, according to Temple, was in an agony when left alone at Nymwegen. On the other hand, his knowledge of the civil law and diplomatic usage was very great, his industry was indefatigable, and his loyalty unimpeachable. Roger North calls him 'the most faithful drudge of a secretary that ever the court had.' He was a stiff churchman, a sincere believer in the divine right of kings, and of an exemplary life. North, however, says that he was 'inclined to laugh immoderately at a jest, especially if it were' coarse, which Charles discovering, 'failed not, after the tendency of his own fancy, to ply his secretary with conceits of that complexion.' His excessive modesty and suavity brought upon him the unmerited suspicion of timidity. During his long tenure of office in the admiralty and prerogative courts he did much to elucidate the principles and improve the practice of the law. The Statute of Distributions and in part the Statute of Frauds are his work, and he strove hard, but in vain, to pass a bill 'to ascertain the jurisdiction of the admiralty' (Roger North, Lives, i. 229, 232; Burnet, Own Time, fol., i. 481-2; Hist. MSS. Comm. 9th Rep. App. p. 49 a). His despatches from Cologne and Nymwegen, with some letters, including one to the Duke of York urging the duke to return to the communion of the church of England (one of the two letters appended to Samuel Parker's 'Discourse sent to James II to persuade him to embrace the Protestant Religion,' 1690, 4to), and some speeches, charges, and legal opinions, rightly styled by Wheaton 'a rich collection of precedents on the maritime law of nations;' his argument before the House of Lords in support of the admiralty bill, a locus classicus on the history of the admiralty court, and other miscellanea, will be found in his 'Life' by William Wynne, 1724, 2 vols. fol. 'An Exact Collection of the most considerable Debates in the honourable House of Commons at the Parliament held at Westminster, 21 Oct. 1680,' &c., appeared under his name in 1681 (8vo), and does not seem to have been disowned; but, as he was notoriously opposed to the publication of the transactions of the house, it is probably not authentic.
[The principal authorities are: Life by Wynne referred to above; Wood's Fasti Oxon. ed. Bliss, ii. 231-3; Biog. Brit. and Coote's Cat. of English Civilians; Bulstrode's Memoirs, ed. 1721, pp. 304 et seq.; Luttrell's Relation of State Affairs, i. 35, 42, 207, 262, 292, 305, 354; Hatton Corresp. (Camden Soc.), i. 225; Parl. Hist. iv. 1182, 1190, 1205, 1289, 1313-17, 1333, 1338; Secret Services of Charles II and James II (Camden Soc.), p. 87; Dalrymple's Memoirs, 2nd edit. App. pp. 302 et seq.; Groen van Prinsterer's Archives de la Maison d'Orange-Nassau, 2ième série (Utrecht, 1861), vol. v.; Wood's Hist. and Antiq. of Oxford, ed Gutch, iv. 578, 586; Burnet's Own Time, fol., i. 354, 422-3, 439-40, 481-2, 528-31; Temple's Memoirs of what past in Christendom from the War begun 1672 to the Peace concluded 1679; Saint-Disdier's Hist. des Négotiations de Nimègue; Dumont's Corps Dipl. tom. vii. pt. i. pp. 253, 283, 305, 325-50 et seq.; De Garden's Hist. des Traités de Paix, vol. ii. chap. vii.]