This interesting surname is English and locational. It originates from the village of Thirlwall in Northumberland, which itself is pre 7th Century and means "The perforated wall". The village is on the famous Hadrians or Roman Wall, which must have had a gap or gate at this point allowing traders and merchants to pass through. The place name is first recorded as Thurlewall in the Assize Rolls of Northumberland in 1256. The first recording of the surname (see below) appears to pre-date the village name, which is not possible, and suggests either that there were no earlier written entries for the village or more likely that they have been lost. Examples of the surname recordings include John de Thirlewall in 1386, and Rouland de Thirwall in 1460, both appearing in the "History or Northumberland". Church recordings include Eleanor Thirlwall who married John Errington on November 9th 1579, at Hexham, Northumberland, Johanna Thirlewall married Nicholas Robison on November 16th 1586, also at Hexham, whilst in London John Thirlwall was christened on July 23rd 1721, at St. Anns Blackfriars. Connop Thirlwall (1797-1875) was a historian and bishop of St. David's. He is buried in Westminster Abbey. The first recorded spelling of the family name is shown to be that of Richard de Thurlewall. This was dated 1216, in the History of Northumberland, during the reign of King Henry 111rd of England, 1216 - 1272. Surnames became necessary when governments introduced personal taxation. In England this was sometimes known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.