Thomas Sydserf [Sydserff] (1581 – 1663) was a Scottish prelate.
The eldest son of James Sydserf,an Edinburgh merchant, Sydserf graduated from the University of Edinburgh in 1602 before travelling to continental Europe to study at the University of Heidelberg.After returning to Scotland, he entered the ministry, beginning at St Giles' parish, Edinburgh in 1611.15 years later, in 1626, he was translated to Trinity College Kirk, Edinburgh, before being admitted Dean of Edinburgh on 19 February 1634.
However, in the same year, and on the recommendation of William Laud, Archbishop of Canterbury, he ascended to episcopal rank, receiving consecration as Bishop of Brechin on 29 July.In the following year, on 30 August 1635, he was translated as Bishop of Galloway.
Sydserf was very much a royalist, pro-Episcopacy, and inclined to be highly sympathetic towards Arminianism.These views brought him much conflict in Scotland, and as Bishop of Galloway he exercised his episcopal powers against his ideological opponents.He supported the introduction in 1637 of an English-style Book of Common Prayer, and for this he was attacked on several occasions by mobs in Falkirk, Dalkeith and Edinburgh. Some went further and accused him of being a Roman Catholic: he was alleged to wear a crucifix.He was finally deposed by the General Assembly of the Scottish church on 13 December 1638.
Sydserf thereafter went to England, briefly becoming a follower of King Charles I, before moving to continental Europe. He returned to Scotland, and after the Restoration and reimposition of Episcopacy in Scotland, was reinstated as a bishop, though on this occasion becoming Bishop of Orkney.He was the only pre-1638 bishop to be reinstated as a bishop in Scotland after the Restoration.He lobbied hard to be made Primate of Scotlandbut without success. His willingness to ordain as a clergyman anyone who asked himattracted much criticism,a factrecorded by Samuel Pepysin hisfamous diary.
Sydserf died in Edinburgh on 29 September 1663.In 1624 he had married Rachel Byers, the daughter of an Edinburgh magistrate: they had four sons and four daughters, including Thomas junior, a popular dramatist and journalist.
Sydserf was responsible for remodelling the nave of Whithorn Priory in line with the new styles or worship he tried to promote.
Although notformally a member of the Hartlib Circle, he wason friendly terms with some of its members includingArnold Boate, who dedicated to Sydserfhis memoir of his wife Margaret Dongan.