John Nelson is the earliest recorded Englishman known to have converted to Islam. The source of this information comes from the book, The Voyage made to Tripoli (1583) by Thomas Saunders, cited by Nabil Matar (1998).

He was a “son of a yeoman of our Queen’s Guard… His name was John Nelson”

Many more had converted or ‘turned Turk’ or become ‘renegados’ (renegades) before him but he is the first Englishman recorded by name.