In Enkhuizen, the fifth major town in the region of Holland at the time, dozens of portraits were painted in the last years of the sixteenth and first decades of the seventeenth century. ln 1934 A. B. de Vries acknowledged a few paintings of 1594 and 1595 (cat. nos. 3, 4 and 5) as the work of an artist who was active in Enkhuizen and a follower of the Amsterdam painters Pieter and Aert Pietersz. It transpires that a large number of other portraits can be attributed to that same painter. Thanks to the fact that a print by Willem Delff after one of the works in this group, a portrait of Henricus Antonii Nerdenus of 1604 (fig. 5) bears the inscription Ioan.Nicol.Enchus.pinx., the anonymous Enkhuizen artist can be identified as one Jan Claesz. Archive research has yielded only a series of entries in notarial deeds of 1613 - 1616, but the painter's works facilitate the construction of a brief biography. Jan Claesz. was probably born around 1570 or a little earlier in or near Enkhuizen, and trained with Pieter or Aert Pietersz. in Amsterdam. The young artist painted a few portraits in that city in 1593. Shortly afterwards he moved to Enkhuizen, where, j udging by his paintings, he was certainly active until 1618. He probably died that year or a little later. As far as can be established he confined himself to portraiture. The earliest known attributable works are his portraits of Bartholomeus van der Wicrc and his wife, painted in 1593 (figs. 7 and 8) and clearly showing the influence of Pieter and Aert Pietersz. The compositions and poses are characteristic of Jan Claesz.'s work; the background perspective does not quite come off. His portraits of two sisters of 1594 (figs. 9 and 10) are less ambitious, and are among the most attractive Netherlandish children's portraits of the late sixteenth century. Very similar is a portrait of Reynu Semeyns, painted a year later (fig. II), which displays the same painstaking method. This picture once had a companion piece, a portrait of the famous explorer Jan Huygen van Linschoten which is only known from a copper engraving with a partial copy in mirror image (fig. 12). This print suggests a close relationship between the portrait of Van Linschoten and a painting of 1598 in which Adriaen Teding van Berkhout is depicted (fig. 13). In 1598 Jan Claesz. also painted a full-length portrait of a child standing on a tiled floor, with two pilasters and an arch in the background (fig. 14), an arrangement he used on a number of subsequent occasions (figs. 23, 24, 26 and 27). A separate group in Jan Claesz.'s œuvre consists of three double portraits of 1601 and 1602, featuring an adult wih a child (figs. 15, 16 and 17); the companion pieces of 1602 demonstrate that the painter not only worked for Enkhuizen patrons but also for the regents in the neighbouring town of Hoorn. A few portraits of older people painted between 1603 and 1608 (figs. 2, 3, 18, 19 and 20) clearly show the minute detail in the painting, sometimes resulting in a certain hardness in the rendering. A portrait of a boy of 1608 (fig. 21) suggests that the artist was familiar with the interest evinced in other towns for giving portraits trompe-l'œil frames. Another portrait of a boy painted a year later (fig. 22) is the earliest known example of a type of children's portrait that was especially popular in West Frisia in the seventeenth century; the subject is a boy with a miniature horse. A child's portrait previously attributed to Adriaen van der Linde, a painter active in Frisia, but consistent in every aspect with other paintings by Jan Claesz., dates from the same period (fig. 24). A similar portrait, probably depicting Claes Gerritsz. Slijper and painted in 1614, has suffered considerably from overpainting of the head (fig. 28). A few portraits of adults dating from 1616-1618 (figs. 33, 34 and 36) are the last known works of the painter and among the best he ever did. Like other paintings by Jan Claesz. (figs. 1 5 and 35), they also give us an idea of the rich traditional costume of Enkhuizen. Jan Claesz. may be regarded as a representative of the generation of portraitists who in the waning sixteenth and dawning seventeenth century laid the foundations for the heyday of portraiture in the ensuing years of the seventeenth century. He is also a representative of the widespread influence of the painters Pieter and Aert Pietersz., an influence particularly noticeable in the northern region of the Netherlands. He added his own elements to their example. His fairly numerous portraits of children, with their somewhat naive charm, form an important contribution to our knowledge of the North Netherlandish children's portrait of around 1600.