Guillaume Delisle 1675-1726 Known as the father of modern cartography, was educated by his father, Claude. In 1700 he began work as a compiler and publisher of maps, his first works were "The Map of the World" and "The Map of the Continents” . These and the terrestrial maps produced subsequently, which surpassed all similar publications, established his fame and for the rest of his life. Delisle adopted entirely new principles in cartography and set about making a thorough reform in that subject. The map-publishers of the time did not know how to utilize the material supplied mainly by the French astronomers of the latter half of the seventeenth century, and Delisle recognized that the new methods of measuring by scale and of marking the places were very valuable for cartography; with this help he therefore produced a new and more accurate picture of the world. He soon gained an international reputation, and scientists and kings (Peter the Great and Louis XIV) paid him visits. Delisle was named Premier Geographe du Roi, the first in France to be granted such a title. His chief merit was his application of scientific methods and careful examination of original sources. Unlike earlier cartographers, Delisle left blanks representing unknown areas rather than fabricating hypothetical features. He was the first to correct the longitudes of America, to discard the fallacy that California was an island, to delineate the Mississippi Valley correctly, and to introduce many new place names.