 Most of the papers sent to Paris were on astronomical questions, and among these including his paper on the Jovian system in 1766, his essay on the problem of three bodies in 1772, his work on the secular equation of the Moon in 1773, and his treatise on cometary perturbations in 1778.These were all written on subjects proposed by the Académie française, and in each case the prize was awarded to him.Between 1772 and 1788, Lagrange re-formulated Classical/Newtonian mechanics to simplify formulas and ease calculations.