This interesting and uncommon surname, recorded in English church registers from the mid 16th Century, under the variant spellings Colthurst, Colthirst, Caulthurst, Colethurst etc., is of locational origin from a place north west of Clitheroe in the West Riding of Yorkshire called Colthurse. The component elements of the placename are either the Old English pre 7th Century "colt", cott, or the Old English byname Cola from "col", charcoal, denoting someone of swarthy appearance, plus the Old English "hyrst", a wooded hill. On April 23rd 1560, Joan Colthurst and John Walker were married in St. Lawrence Jewry and St. Mary Madgalene Milk Street, London, and on November 2nd 1567, John Coolthurst and Elling Cower were married in Gargrave, Yorkshire. The marriage of Pauline Coulthurst and Christopher Wilkinson took place in Gisburn on April 23rd 1598. A Coat of Arms granted to the Coulthurst family of Gargrave, Yorkshire, depicts a fesse or central band between two black colts. passant on a silver between two black colts. Passant on a silver shield. The fesse is emblematic of the military girdle worn round the warriors waist. The first recorded spelling of the family name is shown to be that of Gracia Coltherst, (christening), which was dated October 15th 1559, Halifax, Yorkshire, during the reign of Queen Elizabeth 1, "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.