This portrait was made in about 1620, when Anthony van Dyck was only 21 years old – the rising star of his generation, and soon to become one of the best-known portrait painters in Europe. The sitter, on the other hand, is Cornelis van der Geest, who was 65 and a grand old man of the arts.

A prosperous and influential Antwerp spice merchant, van der Geest was one of the most prominent collectors of paintings of his day. He was so revered that Van Dyck’s famous teacher Rubens described him as ‘the best of men and my oldest friend, who, since my youth, has been my never-failing patron, whose whole life showed a love and admiration of painting’. And if we doubted Rubens’s word, a painting of the interior of van der Geest’s house in 1615 by Willem van Haecht (now in the Rubenshuis, Antwerp) shows his extensive collection of pictures by some of the most important Flemish artists of the sixteenth and seventeenth centuries.

So for the young Van Dyck, in the early stages of a career in portrait painting, a commission from such an influential patron must have been extremely important. He certainly rises to the occasion, though not by showing off a radically new approach to the composition, as some young artists might have done. Instead he has taken – or perhaps van der Geest asked him to take – a relatively conservative approach using a traditional format: a close up of the sitter’s face framed by a white ruff. What sets the painting apart is Van Dyck’s virtuoso brushwork.

For the hair and beard he employed long, wispy strokes, while elsewhere he used much thicker paint – to add texture to the edges of the ruff, for example, or for the edges of the lower eye lids, which are modelled in three dimensions with thick ridges of paint. The moisture in van der Geest’s eyes is evoked with delicate flecks of white paint. The positioning of van der Geest’s head and gaze is also subtly effective. He looks very slightly back and down at us, enhancing the illusion that he has reacted to the viewer and that we are encountering a real person.

The picture we see today is somewhat different to what left Van Dyck’s workshop. X-ray photographs show that, instead of the plain dark background, the portrait was originally set in a simulated oval frame painted to look as though it were made of porphyry (a type of red stone). This was a device which Van Dyck used in at least one other picture around this time (Portrait of a Man, Musées Royaux des Beaux-Arts, Brussels). Part of the white ruff has also been painted over by a later hand; it was originally higher at the back, up around the level of his right eye on one side and above his ear on the other.

Probably less than 15 years after it was made, new pieces of oak were added to the sides and bottom, and the painting was extended into a bust-length portrait which also showed his left arm. This extension was almost certainly not done by Van Dyck. The large frame now covers the additions so that they are not apparent.