Thomas de Keyser was the second son of Hendrick de Keyser (1565–1621), the famed Dutch architect, sculptor, and municipal stonemason of the city of Amsterdam, and his wife Beyken (Barbara) van Wildere, who hailed from Antwerp. The family lived in a house that was part of the municipal stone yard along the Amstel River, between the Kloveniersburgwal and the Groenburgwal. Thomas and his brothers Pieter and Willem were trained by their father in architecture, and each also became a highly regarded master stonemason and stone merchant in his own right. On January 10, 1616, the approximately 19-year-old Thomas became one of his father’s apprentices. As he must already have become proficient at the trade while growing up at the Amsterdam stone yard, the formal two-year apprenticeship that followed would have fulfilled the stonemasons’ guild requirements.
Thomas, however, achieved his greatest prominence as a painter and became the preeminent portraitist of Amsterdam’s burgeoning merchant class, at least until the arrival of Rembrandt van Rijn (Dutch, 1606 - 1669) in 1632. Nothing is known about his artistic training as a painter, which likely occurred in his younger years. Four Amsterdam portraitists have been considered his possible teacher. Ann Jensen Adams, in her catalogue raisonné of Thomas de Keyser, posits (based on circumstantial evidence) that Cornelis van der Voort (c. 1576–1624) was most likely his master. Similar circumstantial evidence could argue for a formal artistic apprenticeship with Cornelis Ketel (1548–1616), as strong stylistic similarities exist between De Keyser’s early bust-length portraits and those of Ketel, who was a good friend of Hendrick de Keyser. Furthermore, in the late 1620s and early 1630s, Thomas de Keyser received six important commissions for full-length group portraits, a type of painting that Ketel had introduced into the Netherlands in 1588.
Thomas de Keyser gained lasting renown for two significant innovations in Dutch portraiture. First, he began to paint the Dutch elite in full-length formal portraits, a format hitherto reserved for the aristocracy, but he drastically reduced the scale of such portraits to make them suitable for his patrons’ urban homes. He also began to depict subjects in their personal or professional environments, thereby bridging the fields of portraiture and domestic genre scenes. De Keyser created many of his best works on copper panels, whose exceedingly smooth surface allowed him to paint with a great deal of refinement.
Despite his fame as a portraitist, De Keyser produced slightly fewer than one hundred paintings. He created the bulk of his oeuvre in the period between 1624 and 1639, after which his primary focus shifted back to the lucrative international stone trade, yielding the Amsterdam portraiture market to Rembrandt, Govaert Flinck (Dutch, 1615 - 1660), and Bartholomeus van der Helst (1613–1670). De Keyser registered as a master in the stonemasons’ guild on May 14, 1640, but never completely abandoned the fine arts. In the last decade of his life, he became known for several finely executed small-scale equestrian portraits. Following in his father’s and older brother's footsteps, from 1662 until his death in 1667 he served as Amsterdam’s chief city-stonemason (stads-steenhouwer), in which capacity he supervised the construction of the cupola atop the new Amsterdam Town Hall (now the Royal Palace) on Dam Square.
 This biographical account owes much to Ann Jensen Adams, “The Paintings of Thomas de Keyser (1596/7–1667): A Study of Portraiture in Seventeenth-Century Amsterdam” (PhD diss., Harvard University, 1985), 1:18–27. See also A. W. Weissman, “Het geslacht De Keyser,” Oud Holland 22, no. 1 (1904): 65–90. Thomas’s youngest brother, Hendrick the Younger, became a stonemason under the tutelage of their brother-in-law, Nicholas Stone, in London. Stone had started his own career as apprentice to Hendrick de Keyser the Elder around the turn of the century.
 For a description of the stads steen-thuyn, see Tobias van Domselaer, Beschryvinge van Amsterdam (Amsterdam, 1665), 282. The Amsterdam stone yard is clearly visible in Floris Balthasarsz Van Berckenrode’s 1625 map of Amsterdam (Rijksmuseum, Amsterdam).
 On the training of Pieter and Willem de Keyser and their entry into the St. Luke’s Guild, see W. H. F. Oldewelt, “Het St. Lucasgilde,” in Amsterdam Archiefvondsten (Amsterdam, 1942), 91; and Ann Jensen Adams, “The Paintings of Thomas de Keyser (1596/7–1667): A Study of Portraiture in Seventeenth-Century Amsterdam” (PhD diss., Harvard University, 1985), 1:29.
 Adams lists four possible Amsterdam masters, who all primarily produced portraits: Cornelis Ketel, Aert Pietersz (c. 1550–before 1612), Pieter Isaacsz (1569–1625), and Cornelis van der Voort. Ann Jensen Adams, “The Paintings of Thomas de Keyser (1596/7–1667): A Study of Portraiture in Seventeenth-Century Amsterdam” (PhD diss., Harvard University, 1985), 1:30–35. In 1885 Nicolaas de Roever proposed Pieter Isaacsz. The next year Jan Six expressed his disagreement and suggested that Thomas was taught by Ketel. J. Six, “Nicholaes Eliasz Pickenoy,” Oud Holland 4 (1886): 101 n. 1. In his catalogue raisonné, Rudolf Oldenbourg also identified Ketel as Thomas’s teacher. Rudolf Oldenbourg, Thomas de Keysers Tätigkeit als Maler: Ein Beitrag zur Geschichte des holländischen Porträts, Kunstwissenschaftliche Studien 7 (Leipzig, 1911), 15–16, 15 n. 1, 44–45.
 Quentin Buvelot describes Ketel's portraits as showing the sitter “very close to the picture plane, from an unusual angle, and cropped closely by the frame.” Rudi Ekkart and Quentin Buvelot, eds., Dutch Portraits: The Age of Rembrandt and Frans Hals (Zwolle, 2007), 180.
 Ann Jensen Adams, “The Paintings of Thomas de Keyser (1596/7–1667): A Study of Portraiture in Seventeenth-Century Amsterdam” (PhD diss., Harvard University, 1985), 1:326, 2:84–94, no. 45. The Company of Captain Allaert Cloeck and Lieutenant Lucas Jacobsz Rotgans (1632, Amsterdam Museum, inv. SA 7353) is an excellent example of De Keyser’s exquisite brushwork and sensitive renderings of personality. For an extensive description of this militia portrait and its preliminary drawings, see the Thomas de Keyser entries in Ger Luijten, Peter Schatborn, and Arthur K. Wheelock Jr., Drawings for Paintings in the Age of Rembrandt (Milan, 2016), 132–135, nos. 45, 46. For Ketel’s groundbreaking full-length group portrait The Company of Captain Dirck Jacobsz Rosecrans and Lieutenant Pauw (1588, Rijksmuseum, Amsterdam, SK-C-378), see Hessel Miedema and To Schulting, “Het Schuttersstuk van Cornelis Ketel (1588),” Bulletin van het Rijksmuseum 39, no. 4 (1991): 355–362.
 Ann Jensen Adams, “The Paintings of Thomas de Keyser (1596/7–1667): A Study of Portraiture in Seventeenth-Century Amsterdam” (PhD diss., Harvard University, 1985). See also Eric Jan Sluijter, Rembrandt’s Rivals: History Painting in Amsterdam (1630–1650), Oculi: Studies in the Arts of the Low Countries 14 (Amsterdam, 2015), 272–284, 437–438 (notes); and Norbert Middelkoop, ed., Kopstukken: Amsterdammers geportretteerd 1600–1800 (Bussum, 2002), 31–33, 90, no. 4; 140–141, no. 35; 158–159, no. 47; 202–203, no. 72.
 Wilhelm Martin, De hollandsche schilderkunst in de zeventiende eeuw: Rembrandt en zijn tijd (Amsterdam, 1936), 1:312–318.
 The stonemasons’ guild records show that Thomas registered as a master in 1640, yet a few paintings executed in the years 1656 to 1661 prove that he never totally gave up on his artistic career. De Keyser also made history paintings, including a copy after Pieter Lastman’s stained-glass window in the Zuiderkerk at the time of the window’s removal in 1660.
 A. W. Weissman, “Het geslacht De Keyser,” Oud Holland 22, no. 1 (1904): 82; A. W. Weissman, “De Koepeltoren van het Stadhuis te Amsterdam,” Amstelodamum Jaarboek 2 (1905): 6; and Ann Jensen Adams, “The Paintings of Thomas de Keyser (1596/7–1667): A Study of Portraiture in Seventeenth-Century Amsterdam” (PhD diss., Harvard University, 1985), 1:418–419, 440. Apart from a design for a triumphal arch, published in Salomon de Bray’s Architectura Modernaofte bouwinge van onsen tyt (1631), pl. xliiii, no architectural plans with building designs by De Keyser are known.
December 9, 2019
Weissman, A.W. "Het geslacht De Keyser." Oud Holland 22 (1904):65-90.
Weissman, A.W. "Een Brief Van Thomas De Keyser." Oud Holland 34 (1916): 61-66.
Hofstede de Groot, Cornelis. "Pieter Lastman en Thomas de Keyser." Oud Holland 47 (1930): 237-240.
Adams, Ann Jensen. "The Paintings of Thomas de Keyser (1596/7-1667): A Study of Portraiture in Seventeenth-century Amsterdam." 4 vols. in 2. Ph.D. dissertation, Harvard University, Cambridge, Massachusetts, 1985.