The present portrait of a cartographer would appear to date to the first quarter of the 17th Century, and shows a celestial globe designed and issued by Willem Jansz Blaeu in 1602, confirmed by the representation of a particular constellation in the painting of the globe. Given the age of the sitter is recorded by the inscription as thirty-eight years old, if it were indeed to depict Blaeu, the picture would be dateable to 1609.
Blaeu's likeness at this time is known from three engravings that appear in the margins of his maps, in which he is shown with a beard. A later, bust-length portrait of Blaeu in a feigned oval by Thomas de Keyzer (Amsterdam c.1596-1667), after which there is an engraving by Jeremias Falck, also bears some comparison to the present sitter.
Willem Jansz Blaeu was the son of a successful herring salesman, but rather than follow his father into the family business, his natural propensity for and interest in mathematics and astronomy led him to study with the Danish astronomer Tycho Brahe between 1594 and 1596, during which time he qualified as an instrument and globe maker. On his return to the Netherlands, Blaeu made country maps and world globes, purchasing his own printing works to produce atlases, some of which appeared in the Atlas Novus, published 1635. He was appointed map-maker to the Dutch East India Company in 1633.