Rupert left a son, Dudley Bard, born about 1666, and killed 13 July 1686 at the siege of Buda. To him Rupert left some property in Holland, and the debts due from the emperor and the elector palatine. Frances Bard, who claimed to be married to Rupert, is often mentioned in the correspondence of the electress Sophia, at whose court she long resided, and by whom she was treated with great favour (English Historical Review, July 1896, p. 527; Warburton, iii. 466).
In his youth Rupert was handsome and prepossessing. He was very tall, strong, and active. He was reputed a master at all weapons, and Pepys describes him in 1667 as one of the best tennis-players in England (Diary, 2 Sept. 1667). Of his appearance in later years, Grammont observes: ‘Il était grand, et n'avait que trop mauvais air. Son visage était sec et dur, lors même qu'il voulait le radoucir’ (Mémoires de Grammont, ed. 1716, p. 252). A gentleman who served under him in the civil wars describes him as ‘always very sparkish in his dress;’ ‘the greatest beau’ as well as ‘the greatest hero’ (SIR EDWARD SOUTHCOTE; MORRIS, Troubles of our Catholic Forefathers, i. 392). In a narrative of one of his battles it is said: ‘The prince was clad in scarlet, very richly laid in silver lace, and mounted on a very gallant black Barbary horse.’
Portraits of Rupert, painted and engraved, are numerous. The one by Vandyck, representing him aged 12, now in the Imperial Museum at Vienna, is one of Vandyck's finest works; it is engraved in Guiffrey's ‘Antoine Van Dyck,’ 1882. The National Portrait Gallery possesses a half-length by Lely and a miniature by Hoskins. Another by Vandyck is in the possession of the Earl of Craven, and the Marquis of Lothian has a third, representing Rupert with his brother Charles Louis (not Maurice, as stated in the Catalogue). One by Kneller belongs to Lord Ronald Gower; it was engraved by R. White. A portrait by Dobson was finely engraved by Faithorne, and another by Lely (representing him in the robes of the Garter) by A. Blooteling. The Vandyck portrait belonging to the Marquis of Bristol is really of his older brother, Charles Louis, and not of Rupert, as stated in the catalogue of the Vandyck exhibition in 1887.
Like his cousin, King Charles II, Rupert had also a taste for scientific experiments. ‘Il avait,’ writes Grammont, ‘le génie fécond en expériences de mathématiques et quelques talens pour la chimie.’ He devoted much attention to improvements in war material, inventing a method of making gunpowder of ten times the ordinary strength, a mode of manufacturing hailshot, a gun somewhat on the principle of the revolver, and a new method of boring cannon (Warburton, iii. 433; Birch, History of the Royal Society, i. 329, 335, ii. 58). For these purposes Rupert established a laboratory and forge, his labours in which are celebrated in one of the elegies on his death.
Thou prideless thunderer, that stooped so low
To forge the very bolts thy arm should throw,
Whilst the same eyes great Rupert did admire,
Shining in fields and sooty at the fire:
At once the Mars and Vulcan of the war.
(Memoirs of the Life and Death of Prince Rupert, 1683, pp. 74, 80.)
‘Princes-metal,’ a mixture of copper and zinc, in which the proportion of zinc is greater than in brass, is said to have been invented by Rupert. His name also survives in the scientific toys called ‘Ruperts-drops,’ which are said to have been introduced into England by him (cf. Pepys, Diary, 13 Jan. 1662, ed. Wheatley). The invention of the art of mezzotint engraving erroneously attributed to Rupert is really due to Ludwig von Siegen, an able artist, who imparted the secret to Rupert (see J. Challoner Smith, British Mezzotinto Portraits, in which all the facts are given, together with a complete list of the engravings by, and attributed to, Rupert). Rupert showed Evelyn the new way of engraving, with his own hands, on 13 March 1661, and Evelyn published it to the world in his ‘Sculptura, or the History and Art of Chalcography,’ 1662. Evelyn's book gives as a specimen a head representing the executioner of St. John (Warburton, iii. 436, 546; Evelyn, Diary, ed. 1879, ii. 124; cf. H. W. Diamond, Earliest Specimens of Mezzotint Engraving, 1848).
