He became famous for his topographic map of France.
On June 17, 1714, César-François Cassini de Thury, a French astronomer and cartographer, was born. He came from the Italian Cassini family, who immigrated to France in the 17th century. His grandfather, Giovanni Domenico Cassini, was an Italian from Liguria, and during the reign of French King Louis XIV. he became director of the Paris Astronomical Observatory. César-François was born in the French town of Thury-sous-Clermont, some fifty kilometers north of Paris. He became an astronomer like his grandfather and father, Jacques Cassini.
And his son, Jean-Dominique Cassini, was an astronomer, so the family gave a total of four generations of eminent astronomers (contributed to this by the fact that in the Kingdom of France almost all positions, including scientific and political, were hereditary). César-François Cassini de Thury became famous for his topographic map of France, which in his time was unsurpassed in detail and accuracy. This card was completed by his son, the aforementioned Jean-Dominique Cassini, who also received the title of Count.