This unusual name is of early Medieval English origin, and is a locational surname deriving from the small village in Ravenstonedale, in Westmoreland. The place is named from the popular medieval male personal name 'Adam', from the Hebrew name of the first man, according to Genesis, thought to be from the Hebrew word 'adama', earth, with the Middle English 'thwait', from the Old Norse 'thveit', clearing or patch of pasture land. The place was named from the first settler's homestead. Locational surnames were given especially to those former inhabitants who moved to another area, and were best identified by the name of their birthplace. Mary, daughter of Thomas Adamthwaite, was christened at St. James's, Clerkenwell, in London, in 1638. The first recorded spelling of the family name is shown to be that of Reynold Adamthwaite, which was dated 1541, 'History of Ravenstonedale', Nicholls, during the reign of King Henry V111, 'Good King Hal', 1509-1547. 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.