Charles I of England was a Duke.
Charles I ( 19 November 1600 -- 30 January 1649 ) was monarch of the three kingdoms of England , Scotland , and Ireland from 27 March 1625 until his execution in 1649 . A duke ( male ) ( British English : [ uːk ] or American English : [ duːk ] ) or duchess ( female ) can either be a monarch ruling over a duchy or a member of the nobility , historically of highest rank below the monarch . A woman who holds in her own right the title to such duchy or dukedom , or is the wife of a duke , is normally styled duchess .