Cuthbert Tunstall was born at Hackforth near Bedale in North Yorkshire in 1474, an illegitimate son of Thomas Tunstall of Thurland Castle in Lancashire, later an esquire of the body of Richard III, and of his future second wife, a daughter of Sir John Conyers. His parents' subsequent marriage legitimated him under canon and civil law, if not under common law. His legitimate half-brother, Brian Tunstall, the so-called "stainless knight," was killed at the Battle of Flodden in 1513. Sir Walter Scott mentions "stainless Tunstall's banner white" in Canto Six, line 790 of "Marmion".