The entry for ‘Vermuyden, Cornelius’ in the Oxford Dictionary of National Biography, 1885-1900, Volume 58 by Albert Frederick Pollard states that Sir Cornelius Vermuyden had a daughter, Elizabeth who married Sir Thomas Peneystone under the name of Elizabeth Fairmedow. This is not correct and is part of the ‘Fairmedow legend’ propounded when it was noticed over two centuries later that a ‘Sir Cornelius Pharmedo’ was naturalised in 1633 by the Scots parliament (Acta Parl. Scot. v. 58). It was suggested that this was Sir Cornelius Vermuyden with an anglicized form of the name Vermuyden. It was actually a completely different man – Sir Cornelius Fairmedow, whose surname was spelled in many ways.
There is a separate entry in the Oxford Dictionary of National Biography for Sir Cornelius Fairmedow under ‘Fermedo, Sir Cornelius (c.1600–1638)’ by S. P. Cerasano. He was a playwright and a gentleman pensioner who had been knighted on 25 September 1628 at Windsor. Sir Cornelius Vermuyden was knighted some months later at Whitehall on 6 January 1628/9. The two men were actually living in London during the same period but Sir Cornelius Fairmedow died in 1638 while Sir Cornelius Vermuyden lived for almost another forty years.
The Elizabeth Fairmedow who married Sir Thomas Penyston (1626 – 1674) 2nd Baronet of Leigh, was born about 1630 and baptised on 12 July 1630 at St Stephen, Coleman Street, London, and was the daughter of Sir Cornelius Fairmedow (–1638) and his wife Dionysia Stonhouse.
Because of the later confusing of Sir Cornelius Vermuyden with Sir Cornelius Fairmedow, the Oxford Dictionary of National Biography also states that “In his old age Vermuyden seems to have married a second wife, Dionysia Stonhouse.” However Dionysia Stonhouse, the mother of Elizabeth Fairmedow, was the wife of Sir Cornelius Fairmedow and not the wife of Sir Cornelius Vermuyden.
In his 1953 book ‘Vermuyden and the Fens: a study of Sir Cornelius Vermuyden and the Great Level’, Lawrence Ernest Harris debunks the ‘Fairmedow legend’ and describes how it arose. He give details of the Vermuyden family and also states that the “register of the church of St. Margaret,Westminster, contains the record of the burial of “Sr. Cornels Vermooden’ on 15th October 1677”.