Royal Portraits Engravings of Kings & Queens of Great Britain. From the original paintings in the Royal Collection. MaryI became queen on 19th July 1553 after she successfully deposed her first cousin once removed, Lady Jane Grey, or Queen Jane. Jane had been proclaimed queen following King Edward VI’s death July 1553, but her reign was to be only thirteen days. Mary won this game of thrones, imprisoning Jane and eventually executing her. Picture: Lady Jane Grey going to Execution.