This interesting and unusual surname is of Anglo-Saxon origin, and is locational from the villages of East and West Ilsley on the Berkshire Downs, derived from the genitive case of the Olde English pre 7th Century personal name "Hild" (a short form of any of various compound names with the first element "hild", battle, strife) and the Olde English "leah", wood, clearing, hence, "Hild's wood or clearing". The placenames were first recorded as "Hildeslei" in the Domesday Book of 1086, and as "Illeslai" in the Pipe Rolls of 1130. 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. Recorded in the Berkshire Church Registers are the marriage of John Ilsley and Elizabeth Robinson on February 20th 1569 at Cholsey and the christening of Richard Ilsley on March 25th 1581 at Burghfeld. A Coat of Arms granted to an Ilsley family in Berkshire is gold, two bars gemels black in chief three pellets, the Crest being between tow serpents disposed orleways, tails in saltire, a cock proper. The first recorded spelling of the family name is shown to be that of Richard Ilesley (marriage), which was dated November 20th 1550 at Wantage, Berkshire, during the reign of King Edward V1, known as "The Boy King", 1547-1553. 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.