Xenocrates

Xenocrates was a Greek philosopher who led Plato's Academy after Speusippus and systematized Platonic doctrine by introducing the tripartite division of philosophy into logic, physics, and ethics.

Xenocrates systematized Academic Platonism by identifying Platonic Forms with numbers and mathematicals, developing a demonology that influenced later Neoplatonism and early Christian theology, and organizing philosophy into the canonical three-part division adopted by all subsequent schools.