Cassini, Gian Domenico [Giovanni Domenico; Jean Dominique; known as Cassini I] (1625–1712)

Italian-born French astronomer, born in Perinaldo, near Naples. Attracted to astrology in his youth, became Professor at Bologna, during which time he conducted hydrological studies for the Pope to mitigate flooding of the River Po. In 1669 Cassini moved to France and set up the Paris Observatory, remaining director for the rest of his career