Clilverd is of Anglo-Saxon origin, and is a variant form of the English locational name Clifford, from places thus called in Gloucestershire, Devonshire and the West Riding of Yorkshire. Recorded as "Clifort" and "Cliford" in the Domesday Book of 1086 for the above counties, the placename, in all cases, derives from the Olde English pre 7th Century "clif", meaning a cliff, slope or steep bank, and "ford", a ford; hence, "ford on the slope". 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. The surname was first recorded in the latter part of the 12th Century (see below). In the southern English counties, especially in Devonshire, "v" was regarded as the normal pronunciation of "f", and frequently replaced it; hence, the following recording: the christening of Stephen, son of John Clyvferde, at Barnstaple, Devonshire, on January 5th 1572; the marriage of Ann Clevert and Samuel Stroud) at Bideford, Devonshire, on April 17th 1799; and the christening of William, son of John and Ann Cliverd, at St. Andrew's, Holborn, London, on September 13th 1807. The first recorded spelling of the family name is shown to be that of Fulk de Clifford, which was dated 1182, in the "Pipe Rolls of Warwickshire", during the reign of King Henry 11, known as "The Builder of Churches", 1154 - 1189. 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.