JOHANNES VAN KEULEN I Hemels Pleyn / Plani Caelestis, ca. 1680 Various astronomical problems could be solved with the drawn celestial chart, the adjustable armillary sphere and this planisphere. Johannes van Keulen was the founder of a well-known publishing house that was dedicated to the publication of marine atlases and manuals of the sea throughout its bicentenary. Johannes was born in Deventer in 1654, the son of Gerrit van Keulen and Machteld Pouwels. It is assumed that the family moved to Amsterdam after 1656. Johannes joined the local booksellers’ guild in 1678. Between 1681 and 1684 he published his most important work, De Nieuwe Groote Ligtende Zee-Fakkel, in five volumes. In addition to books and sea charts, navigators could buy all kinds of navigational instruments, such as quadrants and protractors, from his shop. Johannes van Keulen died in Amsterdam in 1715. His son Gerard, a skilled engraver and mathematician, had already followed in his father’s footsteps in 1704 and continued the business after Johannes’s death. Johannes van Keulen’s most important publications are the navigator’s guide De Groote Ligtende Zee-Fakkel (1681-1684) and the Zee-atlas ofte Water-werelt (1695). As Johannes van Keulen was not a cartographer, he worked closely with the mathematician Claes Janszoon Vooght. Vooght was the creator of most of the maps published by Johannes van Keulen. The Groote Ligtende Zee-Fakkel contained for the first time in history the cartography of the coasts of the whole world, with the exception of the Dutch East Indies (these maps were kept secret by the Vereenigde Oost-Indische Compagnie). At the end of the 17th century, Johannas van Keulen was the leading publisher of sea charts in Amsterdam.