Sir Leoline Jenkins (1625 – 1 September 1685) was a Welsh academic, diplomat involved in the negotiation of international treaties (e.g. Nimègue), jurist and politician.
On the failure of the Royalist cause, he retired to Glamorgan in 1648, and entered the household of the Welsh Royalist Sir John Aubrey, first of the Aubrey baronets, at Llantrithyd, as did his two most valuable patrons, Gilbert Sheldon, the future Archbishop of Canterbury, and Sir Francis Mansell, Jenkins' predecessor as Principal of Jesus College.
He set up a small private school for the education of Aubrey's son and other local boys, but it was broken up by Parliament in 1651 as a seminary for potential traitors.
On the death of the queen mother Henrietta Maria at Colombes in August 1669, Jenkins was sent to Paris to argue that the disposition of her personal property was governed by English, not French law: the result would be that the property would pass in its entirety to Charles II, rather than to his sister Henrietta, Duchess of Orleans, who would have been the beneficiary under French law.
Whilst Secretary of State, he was served by the Welsh lawyer (and former student of Jesus College) Owen Wynne, who has been called "an early example of the permanent civil servant.
At a meeting of the Privy Council in October 1681, some of the Councillors, Jenkins wrote to a colleague, "were pleased to fall upon me" for not sharing with them important items of foreign policy.
He argued that the Secretaries of State "were not at liberty to carry any part of their intelligences to the Council, unless his Majesty directed it specifically": this was a rule which he had always followed and by which he was "indispensably bound".
[11] In his will, Jenkins stated: "It is but too obvious that the persons in Holy Orders employed in his Majesty's fleet at sea and foreign plantations are too few".
This category of fellowship was abolished in 1877 by the Oxford and Cambridge Universities Commission, without prejudice to the rights of existing holders such as de Winton.