This picture was one of a set of thirteen portraits commissioned by the Duke of York, the Lord High Admiral of the Fleet, following the naval victory over the Dutch at thebattle of Lowestoft on 18 June 1665. Only two of the set remain in the Royal Collection, this and RCIN 405153, the rest having been presented by George IV in 1824 to Greenwich Hospital. They are now in the National Maritime Museum. In common with most portraits by Lely, it appears that the heads of the flag-officers are by the master, but the remainder of the compositions are by studio assistants. Prince Rupert (1619–82) is shown wearing a buff coat, which was lighter than full armour yet still provided some protection when combined with a breastplate, as here. Hostilities with Holland led to the outbreak of the Second Anglo-Dutch War in 1665. After an unsuccessful blockade of Dutch ports in May, a fleet of a hundred ships, led by the Duke of York in his flagship the Royal Charles, engaged with the Dutch fleet off the coast of Lowestoft in Suffolk. Prince Rupert, cousin of Charles II and cavalry commander for the Royalist army during the Civil War, was the Vice-Admiral of the Fleet during the battle. English victory came at a high cost: thousands of sailors died and many officers were lost. Other flag officers represented in the series include Edward Montagu, 1st Earl of Sandwich, Admiral of the Blue division and Pepys’s patron; Sir John Harman, captain of the Duke of York’s flagship; and Sir William Penn, Captain of the Fleet. Eight of the portraits, together with one of the Duke of York himself, were recorded in 1671 as hanging in the Great Chamber of the duke’s country residence, Culford Hall in Suffolk: ‘Hung round with green and white silk and thread Damaske with Matte under the hangings, the Dukes picture and eight of the Admiralls viz Prince Rupert, Generalls, Sr Jn Lawsons […] ffive guylt sconces, two chystall Lookeing glasses’.65 By 1688 they were in store at St James’s Palace. Inscribed slightly later: Prince Rupert. Text adapted from Charles II: Art and Power, London, 2017.