Margaret (Madge) Shelton and Mary Shelton (died 1560) were two sisters in Tudor England, one of whom may have been a mistress of Henry VIII of England. Mary was a maid-of-honour and poet. She was the daughter of Sir John Shelton and Anne Shelton (1475 1555), herself a daughter of William Boleyn and Margaret Butler. Her mother's brother was Thomas Boleyn, father of the queen Anne Boleyn; therefore, she and Anne were first cousins. Mary Shelton was a teenage maid-of-honour to her first cousin Anne Boleyn. It is believed that one of the Shelton sisters had an affair with King Henry for around six months, beginning in February 1535, according to Eustace Chapuys, the Imperial ambassador. It has traditionally been believed that this was Margaret, but recent research has led to the claim that it was Mary who was Henry's mistress and who was rumoured to become his fourth wife. Supposedly, this confusion arose from the label "Marg Shelton", where the y looked like a g - a common confusionin sixteenth-century writing. Some historians argue that Margaret and Mary were the same person and not two separate sisters.