This is a name of ancient English locational origin which is rare, but recorded under a variety of different spellings in at least five counties. It derives from the compound 'Claeg' translating as clay, and 'hlaw' - a hillside. It is quite possible that a place actually called Claylaw, Clewlaw or similar, did once exist, some seven thousand medieval places having now disappeared. If so it was probably in the West Midlands area, Staffordshire or Cheshire perhaps, as the greatest concentration of names comes from these counties. The recordings include Johannes Clewlowe of Macclesfield in May 1645, John Clulow of York in September 1675 and the Nottinghamshire variant spelling Of Cluro(w) being first recorded at Plum-tree North Nottinghamshire on March 3rd 1788, when John Cluro was christened. The first recorded spelling of the family name is shown to be that of Robert Clulowe, which was dated May 4th 1563, married Elizabeth Hyne at Astonfield, Staffordshire, 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.