Born about 1691 in Llansanor, Glamorgan, Wales (IGI).
Second son of Sir Francis Gwyn.
Became heir to the estate when his older brother Edmund Prideaux Gwyn died in 1736.
In 1741 became Member of Parliament for Wells.
Married to Lora Pitt, daughter of George Pitt of Strathfieldsay - but she died in 1750.
Second marriage to Frances Combe, daugher and coheiress of Mathew Combe, Winchester.
There were no children from either marriage.
He died on 4 November 1777 childless. In his will dated 6 June 1752 he bequeathed all his lands in Devon, Dorset, Somerset and Glamorgan firstly to his wife; and upon her death to his kinsman John Fraunceis of Combe Florey, Somerset, and his male heirs, on condition that they assumed the name of Gwyn.
According to the Marriage Licence Allegations - Faculty Office 1701 to 1850 quoted on the website http://www.originsnetwork.com/BritishOrigins/BOShowRecordsFO125.aspx
Francis Gwynn married Frances Combe on 17 December 1751