This interesting surname is of Welsh, Cornish, and Irish origins. Taking the Welsh-Cornish origin first Glynn is a locational name from one of the places thus called, such as Glyn Dyffryn, near Corwen, in the county of Merioneth, or Glynn, near Carmarthen or Glynn on the river Fowey, in Cornwall. The placenames derive from the pre 7th century word "glyn", meaning a valley. Locational surnames were developed when former inhabitants of a place moved to another area, usually to seek work, and were best identified by the name of their birthplace. The Irish origin is more complex and is an anglicized form of the Gaelic "Mag Fhloinn", which translates as "The son of the red complexioned one" from "flann", meaning red. The main sept of the clan "Mag Fhloinn" originated in the area of County Westmeath and County Roscommon from where they spread west of the River Shannon, mainly to County Sligo, and north to Donegal. Recorded in the spellings of Mac Glynn, Mac Glennon, Glynn, Glen and Mac Gloin, in 1980 the clan numbered about 4000 persons in Ireland. The clan seems to have been favoured with many members of the priesthood, and some who died protecting the faith. Examples include the Rev Bonaventure Maglin, who fell foul of Oliver Cromwell in 1654, the Rev. Martin Glynn (1729 - 1794), who was the last rector of the Irish College at Bordeaux, and who was guillotined during the French Revolution as a supporter of the king, whilst Martin Henry Glynn (1865 - 1924) was Governor of New York. The first recorded spelling of the family name is shown to be that of James Glynn, which was dated 1617, a grand juror of County Tipperary, Ireland, during the reign of King James 1st of England and V1 of Scotland, 1587 - 1625. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.