Francis Cleyn (or Clein or Franz Klein) (c. 1582–1658) was a painter and tapestry designer.
He was born in Rostock in Germany, and while a youth displayed such abilities that he was retained in the service of Christian IV of Denmark. During this time he painted, in 1611, a half-length portrait of Christian, now in the gallery of Copenhagen, and executed decorative works in the castle of Rosenborg and other places. Here, too, he met Sir Robert Anstruther, then ambassador extraordinary from England to the court of Denmark. 
He was sent to Italy to study, and remained there four years, studying at Rome and Venice ; at Venice he was introduced to Sir Henry Wotton, then English ambassador to the republic. After returning to Denmark, he proceeded to England with letters of introduction from Anstruther and Wotton to Charles, prince of Wales. He found Charles away on his expedition with Buckingham to Spain, but was warmly received by James I, who saw in him the very man he wanted for the new tapestry manufactory which he had recently set up under Sir Francis Crane at Mortlake.
So anxious was he to obtain Clein's services, that he wrote in person to the king of Denmark, requesting that Clein, who had to return to Denmark to finish some work for the king, might be allowed to return to England, and offering to pay all expenses. The request was granted, and Clein returned to England to enter the service of Prince Charles, and was immediately employed at Mortlake. 
On the accession or Charles to the throne in 1625, he rewarded Clein by granting him denization and a pension for life of £l00 per annum. He also built for him at Mortlake a residence near the tapestry manufactory. Here Clein settled with his family, and superintended the copying of cartoons, and designed the frames in which the subjects were enclosed in the tapestry. 
Charles sent down five out of the seven original cartoons of Raphael from the Acts of the Apostles, then recently acquired, to be copied and reproduced in tapestry under Clein's direction. Copies of these were made by Clein's sons, Francis and John, and they were worked into tapestry at Mortlake. These and the other productions of the Mortlake manufactory were held in high estimation, especially in France, and dispersed over the continent. 
A set of six pieces, representing the history of Hero and Leander, from Clein's designs, were at the Louvre in Paris ; and there are some fine pieces of grotesque at Petworth. The grotesques and other ornaments in these works, a line in which Clein appears to have been unrivalled, have always oeen greatly admired, and some modern authorities have had no hesitation in ascribing them to the hand of Vandyck or some more famous painter, ignoring the fact that Clein was spoken of at the time as a second Titian, and as 'il famosissimo pittore, miracolo del secolo.' Clein was also largely employed by the nobility to decorate their mansions. Samples of his work in this line were to be seen at Somerset House, Carew House, Parson's Green, Hanworth Palace, Wimbledon House, Stone Park, Northamptonshire, Bolsover Castle, and the Gilt Room at Holland House, London.
With the civil war there came a check to Clein's prosperity, and we find him chiefly employed in etching and designing illustrations for books ; in 1632 he had already provided the illustrations (engraved by P. Lombart and S. Savery) to Sandys's edition of Ovid's 'Metamorphoses,' of which an edition was published in Paris in 1637. He designed the illustrations, ornamental head-pieces, &c., to the editions of the classics published by Ogilby, viz. 'Æsop's Fables' (1651), 'Virgil' (English edition, 1654, Latin 1658), and 'Homer,' (1660). His designs were engraved by P. Lombart, W. Faithorne, and W. Hollar, and were so much admired that the king of France had those for Virgil copied in a special edition of his own. Clein etched title-pages for E. Montagu's 'Lacrymæ Musarum' (1650), Thomas Fuller's 'A Pisgah-sight of Palestine' (1650), a frontispiece to 'Lysis, or the Extravagant Shepherd,' and perhaps the etchings in the 1654 and 1660 editions of that work. He published in the form of grotesques some sets of original etchings, viz. 'Septem Liberates Artes' (1645), 'Varii Zophori Figuris Animalium ornati' (1645), 'Quinque Sensuum Descriptio' (1646) ; and a friend and contemporary artist, a Mr. English, etched some grotesques (1654), and a humorous piece from Clein's designs.
There are other etchings in the print room at the British Museum, attributed with great probability to Clein. Although he retained his house at Mortlake, he resided for some time in Covent Garden, and died in London in 1658 at an advanced age. 
He left three sons, Francis, John (both mentioned above), and Charles, and three daughters, Sarah, Magdalen, and Penelope. Francis Clein, the younger, was born in 1625, and was buried at Covent Garden 21 October 1650. With his brother John he followed his father's profession, and they both attained repute as draughtsmen and miniature painters. 
It is difficult to distinguish their work from that of their father. A series of drawings of the cartoons of Raphael were found at Kensington Palace ; they bear the dates 1640-1646, are executed on a large scale, and highly finished; some are signed by John Clein, and were evidently executed by him and his brother at Mortlake. They were seen by Evelyn, who states that the brothers were then both dead. Penelope Clein appears to have been also a miniature painter, and to her have been ascribed two miniatures of Cecil, Lord Roos (1677), and Dorothea, daughter of Richard Cromwell (1668), signed P.C. 
This article incorporates text from a publication now in the public domain: Cust, Lionel Henry (1887). "Clein, Francis". In Stephen, Leslie. Dictionary of National Biography 11. London: Smith, Elder & Co. pp. 26–27.
- Worldwide Arts Resources, Francis Cleyn, Artworks in Museum Collections
- Art Cyclopedia, Franz Cleyn
- Hefford, Wendy (2004). "Francis Clein". Oxford Online Dictionary of National Biography.