This interesting surname, with variant spellings Casley, Casely, Causley, Kesley, Caseley, etc., is of English locational origin from one of the estimated seven to ten thousand villages and hamlets that have now disappeared from the maps in Britain. The prime cause of these "disappearances" was the enforced "clearing" and dispersal of the former inhabitants to make way for sheep pastures at the height of the wool trade in the 14th Century. Natural causes such as the Black Death of 1348 also contributed to the lost village phenomenon. The component elements of the name are believed to be the Olde English pre 7th Century personal name "C(e)atta", a byname meaning cat, plus "leah", an open place in a wood, clearing; hence "C(e)atta's clearing". The surname is first recorded in the latter half of the 16th Century (see below). Other recordings of the surname from the Yorkshire church registers include; Sarah, daughter of William and Margaret Caisley, who was christened on January 1st 1755, at Hornsey, and John Caisley married Elizabeth Weight at Foston on the Wolds, on May 14th 1788. The first recorded spelling of the family name is shown to be that of Steven Caslay, witness at christening, which was dated March 10th 1576, in Bilton Ainsty, Yorkshire, during the reign of Queen Elizabeth 1, known as "Good Queen Bess", 1558 - 1603. 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.