[2] His father was an illegitimate son of William Herbert, 1st Earl of Pembroke of the eighth creation (1468), by his mistress, Maud, daughter of Adam ap Howell Graunt.

[2] William Herbert's early life was distinguished by intense ambition coupled with an equally fierce temper and hot-headed nature.

Described by John Aubrey as a "mad fighting fellow", the young Herbert began his career as a gentleman servant to the earl of Worcester.

However, when a mercer called Vaughan was killed by Herbert, after an affray between some Welshmen and the watchmen for unknown reasons in Bristol, he fled to France.

For his service to Henry, Herbert was granted the estates of Wilton, Remesbury, and Cardiff Castle, and his position as a man of means was secured.

[4] He was made a Knight of the Garter in 1549, and created Baron Herbert of Cardiff on 10 October 1551, and 1st Earl of Pembroke (of the tenth creation) the following day, by Edward VI.

It was at Baynard's Castle that the Privy Council met to end the claim of Lady Jane Grey to the throne and proclaim Mary as Queen of England in 1553.

The earl retained his place at court under Elizabeth I until 1569, when he was suspected of favouring the projected marriage between Mary, Queen of Scots, and the Duke of Norfolk.