Lucas Janszoon Waghenaer (c.1553-1606) published the ‘Spieghel der Zeevaerdt’ between 1583-85 with a series of engraved folio sea charts. It was an immediate success and enabled him to remain in touch with the maritime community. This provided him with a constant flow of new enhanced information. Having sold the rights to the work to Cornelis Claesz by the late 1580s he began to formulate a new work to be entitled the ‘Thresoor der Zeevaert’. He chose to use the more familiar horizontal format which his fellow pilots were more familiar with and was easier to handle. He also chose to add considerably more coastal profiles in woodcut within the text with improved sailing instructions.The twenty-two charts were again engraved by Joannes van Doutecum (d.1605). The charts in the ‘Spieghel’ bore Dutch and then Latin titles also. Here the titles are provided in Dutch and French. The coastlines are again displayed in profile although with less detail as the scale is reduced. One new feature is the inclusion of bearing markers for notable landmarks. The work similarly covered western and north western European waters. It too was published by his son-in-law Franciscus Raphelengius and printed again at the Plantijn Press in Leiden in 1592. All subsequent editions were printed by Cornelis Claesz with Waghenaer retaining the rights. This is an entirely new engraved plate, by 1601 the copperplates to the atlas were already worn and had to be replaced. Claesz had them copied by the van Doetecum family, Benjamin Wright, and Joshua van den Ende. The latter’s imprint appears on this plate. Beyond subtle differences there is no real difference from the previous plate. It includes the south coast of Wales, the Bristol Channel, the south west of England and the south coast eastwards to Lewes, Sussex. Unlike many of the charts in the work, there is a considerable amount of cartographic detail inland. It is decorated with two compass roses, two ships, sea monsters, and two cartouche. The upper right one with the French title bears a scale of French miles. A beautifully engraved chart. As the ‘Thresoor der Zeevaert’ was of more practical use at sea, the number of surviving examples is considerably less than the ‘Spieghel’. Indeed, no example could be traced at auction on the ABPC or Rare Book Hub. Koeman IV pp. 502-12 Wag 20 no. 9B; Schilder (2003) MCN VII pp. 62-73; Shirley (2004) M.Wag3a; Skelton (1965) Introduction to Facsimile.