Still another method of doing classical mechanics was put forward by Poisson who lived from 1781 to 1840. Though he was a very prolific mathematician who contributed to a wide variety of fields during his career, we mention his mechanics specifically because of its being at the foundation of the other main formulation of quantum mechanics - Heisenberg's Matrix Mechanics.
In Poisson's formulation, he created a new entity which were called Poisson Brackets, a function involving the Hamiltonian of the system and then some other functional property. Poisson showed how the time evolution of this other property was equal to this Poisson Bracket. We will see later how Heisenberg adapted this to fit his theory.