This is a habitational name with Danish-Viking associations. It derives from the pre 9th Century "Sibba" - a personal name which is a shortened form of the original "Sighbiorn" and was no doubt unspellable by the origin holders. Thorp or Torp referred to a farm or hamlet and in meaning was identical to the Olde English "Tun". The village of (now) Sibthorp, Nottinghamshire, was first recorded in the 1086 Domesday Book as "Sibbethorp". The surname being first recorded in the 13th Century, the original name holder being Anne Sibthorpe of Essex who married one Robert Fovell in 1613 by Civil Licence in London, and Robert Sibthorpe recorded in the Oxford University Register for 1652. The first recorded spelling of the family name is shown to be that of Theobald de Sybethorp, which was dated 1273, in the Hundred Rolls of Nottinghamshire, during the reign of King Edward 1, known as the Hammer of the Scots, 1272 - 1307. 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.