Peregrine was the son of Richard Bertie and Katherine, Duchess of Suffolk, Baroness Willoughby de Eresby. He was born at Wesel on the Rhine in 1555, while his parents were fugitives from England to escape persecution as Protestants under Queen Mary.
After several important diplomatic and military appointments abroad, Elizabeth I appointed him General of her forces in the Low Countries in 1586. He fought for the Huguenots under Henry of Navarre and commanded the English forces assisting Henry at the Siege of Paris in 1590. His military accomplishments are celebrated in the ballad ‘My Lord Willoughby’s Welcome Home’.
Part of the armour in this painting is kept at the Royal Armouries in the Tower of London.
Peregrine’s marriage to Mary de Vere, daughter of the Earl of Oxford brought into the Willoughby family the hereditary office of Lord Great Chamberlain.