The de Grey connection with the castle ended with George de Grey, 5th Baron of Ruthin and 2nd Earl of Kent. After the death of his father, he sold the castle in 1508 to Henry VII from whom it passed to King Henry VIII. Henry VIII was connected to the castle in more than one way. Ida de Grey (1368 – 1426), also known as Edith de Grey, was born in Ruthin Castle and was the daughter of Reginald Grey, 2nd Baron Grey de Ruthyn, one of the most powerful Welsh Marcher lords of his time. Ida married Sir John Cockayne, Chief Baron of the Exchequer by whom she had six children. Through her eldest daughter Elizabeth, she was an ancestress (predecessor) of Anne Boleyn, Jane Seymour, and Catherine Howard, all Queens Consort of Henry VIII. Henry granted use of the castle to his bastard son, Henry Fitzroy, and after his early demise, to Ambrose Dudley, Earl of Warwick (apparently a great man with deep affection for the Welsh and their culture).
Ruthin Castle then passed from Henry VIII to Edward VI and briefly, at least in theory, to Lady Jane Grey. Lady Jane Grey (1536/1537 – 12 February 1554), also known as The Nine Days' Queen, was a descendant of Reginald Grey, 3rd Baron Grey de Ruthyn (c. 1362 – 1440). A young English noblewoman who occupied the English throne from 10 – 19 July 1553 she was executed for High Treason when allegiances changed. A great-granddaughter of Henry VII by his younger daughter Mary, Jane was a first-cousin-once-removed of Edward VI.
Mary I (Bloody Mary) quickly succeeded Lady Jane Grey, and from her the castle passed to Elizabeth I, James I and it’s final royal owner, Charles I.