Claude De L’Isle (1644-1720) was a geographer and historian, working in Paris, but overshadowed by his more famous son, Guillaume.
Guillaume De L’Isle, (1675-1726) Premier Geographe to the French king, was probably the leading map-maker of the period. His work was important, marking a transition from the maps of the Dutch school, which were highly decorative and artistically-oriented, to a more scientific approach, emphasizing the scientific base on which the maps were constructed and out of which the modern school of cartography emerged.
He was prominent in the recalculation of latitude and longitude, based on the most up-to-date celestial observations, and his major contribution was in collating and incorporating this information in his maps, setting a new standard of accuracy, quickly followed by many of his contemporaries, including the Dutch.
His first atlas was published in about 1700, in 1702 he was elected a member of the Academie Royale des Sciences, and in 1718 became Premier Geographe du Roi. His maps of the newly explored parts of the world reflect the most up-to-date information available and did not contain fanciful detail in the absence of solid information.
After his death in 1726 his business was continued by his nephew Philippe Buache, and subsequently by J. Dezauche.
Joseph Nicholas De L’Isle (1688-1768), Guillaume’s brother, became a friend of Peter the Great and supplied him with information on the Russian Empire. He stayed in Russia for twenty-two years and was in charge of the Royal Observatory in St. Petersburg, returning to France in 1747, taking with him much of the material he had access to, particularly relating to explorations along the northern Pacific coasts of Russia and America, which he subsequently published. The Atlas Russicus was published in 1747 and contained twenty maps.
Simon Claude De L’Isle (1675-1726) was a historian. It is interesting to note that he was born and died in the same years as his elder brother Guillaume.