Giovanni Domenico Cassini, or Cassini I, thanks to his leadership, was the first of four successive Paris Observatory directors that bore this family name as a dynastic monarchy. They include his son, Jacques, or Cassini II (1677–1756); his grandson César-François, Cassini III (1714–1784), and his great grandson, Jean-Dominique, Cassini IV (1748–1845). Another descendant, the youngest son of Jean-Dominique, was Alexander-Henry-Gabriel or Cassini V (1781–1832), but even if he also studied astronomy, he devoted himself to botany. The birth and death dates are given in Devic, M.J.F., “Histoire de la vie et des travaux scientifiques de J.D. Cassini IV”, Clermont 1851.