This is an interesting habitational name from the North East of England, although its true origins are pre 9th Century "Viking". It derives from the Norse compound "Thor", a personal name, plus "bekkr", a stream, and although we have no definitive proof, must have referred to a now "lost" area or hamlet probably near to Durham, which is the epicentre of the name. During the period of the "Land Enclosure Acts", from the 15th to the 18th Century as many as seven thousand English "hamlets" were cleared of their inhabitants, and Thirlebecke seems to have been one of them. The name surname recordings from Church Registers include: Willyam Thirlebecke, who was married at St. Nicholas', Durham, on September 10th 1595, whilst Cuthbert Thurlebeck was recorded on August 28th 1595, at Bishop Wear-Mouth. The name appears early in London; Charles Thurlebecke marrying Ann Allumbe at St. Katherine by the Tower, on November 23rd 1690. The first recorded spelling of the family name is shown to be that of Thomas Thirlebecke, which was dated November 30th 1593, marriage to Ann Bell, at Easington, Durham, during the reign of Queen Elizabeth 1, known as "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.