Nicolas Sanson (1600 - 1667) and his descendants were the most influential French cartographers of the 17th century and laid the groundwork for the Golden Age of French Cartography. Sanson started his career as a historian where, it is said, he turned to cartography as a way to illustrate his historical studies. In the course of his research some of his fine maps came to the attention of King Louis XIII who, admiring the quality of his work, appointed Sanson Geographe Ordinaire du Roi. Sanson's duties in this coveted position included advising the king on matters of geography and compiling the royal cartographic archive. In 1644 he partnered with Pierre Mariette, an established print dealer and engraver, whose business savvy and ready capital enabled Sanson to publish an enormous quantity of maps. Sanson's corpus of some three hundred maps initiated the golden age of French mapmaking and he is considered the 'Father of French Cartography.' His work is distinguished as being the first of the 'Positivist Cartographers,' a primarily French school of cartography that valued scientific observation over historical cartographic conventions. The practice result of the is less embellishment of geographical imagery, as was common in the Dutch Golden Age maps of the 16th century, in favor of conventionalized cartographic representational modes. Sanson is most admired for his construction of the magnificent atlas Cartes Generales de Toutes les Parties du Monde. Sanson's maps of North America, Amerique Septentrionale (1650), Le Nouveau Mexique et La Floride (1656), and La Canada ou Nouvelle France (1656) are exceptionally notable for their important contributions to the cartographic perceptions of the New World. Both maps utilize the discoveries of important French missionaries and are among the first published maps to show the Great Lakes in recognizable form. Sanson was also an active proponent of the insular California theory, wherein it was speculated that California was an island rather than a peninsula. After his death, Sanson's maps were frequently republished, without updates, by his sons, Guillaume (? - 1703) and Adrien Sanson (? - 1708). Even so, Sanson's true cartographic legacy as a 'positivist geographer' was carried on by others, including Alexis-Hubert Jaillot, Guillaume De L'Isle, Gilles Robert de Vaugondy, and Pierre Duval.