This interesting and unusual surname is of early medieval English and Old Norse origin, and has two possible sources. Firstly, it may be derived from a short form of any of the following given names: Giles, Julian or William. Giles is ultimately derived from the Latin "Aegidius", from the Greek "aigidion", kid, young goat, and was brought to England by the Normans in the form "Gil(l)e". Julian is derived from the Latin "Julianus", a derivative of "Julius", which is ultimately from "Jovis", the supreme god, whose name is akin to words for "sky, light", and "day". William was introduced into England by the Normans after the Conquest of 1066, and was a favourite name among them; it is derived from the Germanic "wil", will, desire, and "helm", helmet. The second source is from a topographical name for someone who lived by a ravine or deep glen, derived from the Middle English (1200 - 1500) "gil(l)", from the Old Norse "gil", gill of a fish, also used in the transferred sense of a ravine. The surname is particularly well recorded in Yorkshire and Lancashire; the marriage was recorded in Lancashire of Hugh Giller and Margery Rilandson on October 7th 1594, at St. Mary's, Prescot. The first recorded spelling of the family name is shown to be that of Gilbert Giller, which was dated October 26th 1541, marriage to Eme Mathew, at St. Laurence Pountney, London, during the reign of King Henry V111, known as "Good King Hal", 1509 - 1547. 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.