We are grateful to Jean-Claude Boyer for confirming the attribution on the basis of photographs.
We are also grateful to Professor Francesco Petrucci, who will mention this picture in his forthcoming book, Ferdinand Voet, detto Ferdinando dei ritratti, to be published in Rome this year, identifying the sitter as Jean-François Paul de Gondi, Cardinal de Retz. The Cardinal is portrayed in an engraving by Aubert, as well as in portraits by Voet (National Gallery, London) and Carlo Maratti (formerly with Chaucer Gallery, London).
After first studying with Jean Boucher in Bourges and copying the 16th century decorations at the château of Fontainebleau by Rosso Fiorentino, Primaticcio and others, Mignard went to Paris, where in 1633, he entered the studio of Simon Vouet. In 1635, he travelled to Rome, and stayed in Italy until 1657; in 1655 he was called to the Vatican to paint the portrait of the newly elected Pope Alexander VII (untraced, engraving of 1661 by van Schuppen, Paris, Bibliothèque Nationale). In 1658 he went back to Fontainebleau to paint the first of his portraits of Louis XIV, and then, with the exception of a trip to Avignon, stayed in Paris for the rest of his career, replacing Lebrun as Premier peintre du Roi at the age of nearly 80.
Jean-François-Paul de Gondi (1613-1679) became a Cardinal in 1655. He was a leader in the troubles of the Fronde, 1648-52, and travelled in Europe between 1654 and 1662. He died in 1679 and was buried at Saint-Denis, near Paris.