Recorded as Selby, Selbie, and Silby, this is an English surname. It is locational either from the parish and market town of Selby in the East Riding of Yorkshire, or just possibly from Sileby, a village in Leicestershire. Both are called from the pre 7th century Old Norse word "selja" meaning willow and "-by", a farm or settlement. The earliest recording of the placename is as Selby in the early Yorkshire Charters of 1030, whilst Sileby appears as Seglebie in the Domesday Book of 1087, slighly later. This was during the Danelaw, a period when the Vikings ruled most of Northern England. The surname is ancient. As an example the town of Riddleston in Northumberland was granted in 1272 to Sir Walter de Selby, by King Edward Ist of England, and it would seem that it has remained ever since in the possession of his descendants, whilst Johannes de Selby appears in the Poll Tax rolls of Yorkshire in 1379. Early examples of the surname recording in surviving church registers include James Silby at St James Clerkenwell in the city of London in 1611, and Agnes Selby who was christened on September 13th 1618, at Calverley, in Yorkshire. The first recorded spelling of the family name is shown to be that of William de Selebia. This was dated 1175, in the Pipe Rolls of Yorkshire, during the reign of King Henry IInd of England, 1154 - 1189. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.