According to Rodney Horace Yale, in the introduction to "Yale Genealogy and History of Wales;" the family name "Yale" orginated in Wales and was formerly spelled Iāl and Yal (probably Yāl) and comes from the commote, hundred, or district of Yale, in Powys Fadog. Wales. the district of Yale, together with the adjoining district of Bromfield on the west, have formed since the end of the thirteenth centry, a lordship, known as the lordship of Bromfield and Yale. both Bromfield and Yale are in the county of Denbigh.
John Iāl (aka John Wyn or John Wynn,) son of David Lloyd ap Ellis ap Griffith ap Einon, was the first of the Welsh ancestors of American Yale's to adopt the use of Yale in the early Welsh form Iāl, probably because he inherited the Pas-yn-Iāl estate from his father. He did have two brothers who also used the Iāl name however; Thomas and Hugh Iāl.