This most interesting name is of English locational origin from a place called "Gillow" near Tretire in Herefordshire, which was recorded as "Cil luch" circa 1150 in the Liber Landavensis and "Gilloch" and "Killo" in the Inquisitiones Post Mortem of 1280. The placename itself is composed of the Welsh elements "cil", meaning retreat, plus "Ilwch", a pool, hence "a retreat by the pool". During the Middle Ages when migration for the purpose of job seeking was becoming more common, people often took their former village name as a means of identification, hence placenames became a major influence in surname formation. The surname first appears in records in the late 14th Century (see below). One Richardus Gillowe appeared in 1379 in the Poll Tax Records of Yorkshire, as was one Willelmus Gylowe. Two interesting namebearers include a Thomas Gillow (1769 - 1857) who after fleeing the French Revolution became chaplain at Callaly Castle, Northumberland and John Gillow (1753 - 1828) who was president of Ushaw College from 1811 - 1828 and was for twenty years in charge of York Mission. The first recorded spelling of the family name is shown to be that of Willelmus Gyllow, which was dated 1379, The Poll Tax Records of Yorkshire, during the reign of King Richard 11, "Richard of Bordeaux", 1377 - 1399. 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.