Recorded as Kilby, Kileby, Kilsby, and Killerby, this is an English surname. It is locational from either the village of Kilby in Leicestershire, or the similar named villages of Killerby in the counties of Durham and and North Yorkshire. Kilby is first recorded in the Domesday Book of 1086 as "Cilebi" and later as "Kildeby" in 1219, whilst the various Killerby's all appear in the Domesday book as Culuerbi or Chilurobi showing the inability of Norman clerics to understand and translate correctly the strong local accents of those far off times. The translation of the village names may be that of 'The child's settlement' from the pre 7th century Old English and Norse "Cilda-bi". This does not literally mean a child or children, but was a personal name of endearment given either to a first child, or more likely as land ownership is involved, to the eldest child of a local chief. To this has been added the Scandinavian element of "-bi" meaning a settlement or farm. Amongst the early interesting recordings is that of Henry Kilby, who was an early emigrant to the English colonies of the New World, leaving London on the ship "George" in 1635, bound for Virginia. The first recorded spelling of the family name is shown to be that of William de Kilebi. This was dated 1202, in the Assize Rolls of Northamptonshire, during the reign of King John of England, 1199 - 1216. Surnames became necessary when governments introduced personal taxation. In England this was sometimes known as the Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.