A chart of the French coast around the Bay of Biscay from Poitou to Gascony, and part of the coast of the Basque Country, including the mouth of the Garonne River. The inset map shows the Garonne in more detail.

This map appears in the rare English edition of Willem Blaeu’s ‘Het Licht der Zeevaert’, an atlas of sea charts first published in 1608. ‘Het Licht was an early example of a lifetime’s expertise in maritime navigation, which would eventually lead to his appointment as Hydrographer to the Dutch East India Company around 1633. It was produced to update Lucas Waghenaer’s chart atlas ‘Het Spieghel der Zeevaert’ from the 1580s, mimicking the oblong format. ‘Het Licht’ not only amended Waghenaer’s maps but also added “maine new Descriptions and Cardes”. Like ‘Het Spieghel’, Blaeu’s work was designed both as an aid to navigation and also as a primer of navigational skills. It included diagrams demonstrating techniques from using a cross-staff to calculating dates. Blaeu’s apprenticeship at Tycho Brahe’s observatory at Uranienberg is indicated by the inclusion of “new tables of the Declination of the Sonne, according to Tycho Brahe’s observations”.

Blaeu’s aim with ‘Het Licht’ was to win over seafarers, who largely disliked printed manuals. They felt that printed chart books could not be updated with personal observations as easily as the traditional manuscript rutters, and were not as attuned to the concerns of sailors. To counter this, Blaeu introduced innovative new chart symbols for beacons, buoys and shoals to make navigating safer, and made sure that each successive edition of ‘Het Licht’ carried the most up-to-date information. The maps themselves were engraved to the highest quality, possibly by Joshua van den Ende, to emphasise their clarity and ease of use. Blaeu was successful, and ‘Het Licht’ underwent twenty successive editions in French, German and Latin, as well as English.