An astronomer from a family of scientific men, Cassini was born at the Paris Observatory on June 30, 1748. In 1770, he entered the Royal Academy of Sciences and would gradually take his father's place at the Paris Observatory. During the Revolution, Cassini was commissioned to rethink the system of measurement. He thus set about devising the metric system. Cassini also participated in the plotting of a general map of France. His aristocratic background brought him into conflict with the National Assembly, who began opposing his plans for the Observatory. He eventually resigned and was subsequently imprisoned. Released seven months later, he withdrew to his provincial château de Thury.