This interesting surname derives from the Old Norse personal name "Kalfr", originally a byname meaning "Calf", or possibly from the Old English pre 7th Century "calf", Anglian form of "cealf" meaning "calf", used either as a nickname or as a metonymic occupational name for someone who was responsible for tending calves. The surname dates back to the mid 12th Century, (see below). Further recordings include one Alwin Calf (1176) "The Pipe Rolls of Buckinghamshire", Nicholas Calf "The Hundred Rolls of Gloucestershire", and Cicilia Calff (1379) "The Poll Tax Records of Howdenshire". Church recordings include one Alice Calfe who married Anthony Eaton on February 10th 1576 at St. Olaves, Mary Street, London, Elizabeth, daughter of Joseph and Mary Calfe, was christened on March 17th 1622, at Allhallows, London Wall, and Joyce, daughter of Peter and Alice Calf, was christened on May 4th 1643, also at Allhallows, London Wall. The first recorded spelling of the family name is shown to be that of Robert Calf, which was dated 1163, Documents illustrative of the Social and Ecomomic History of the Danelaw, 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.