 Although the main focus of his work was on medicine, anatomy, and physiology, Galen also wrote about logic and philosophy.His writings were influenced by earlier Greek and Roman thinkers, including Plato, Aristotle, the Stoics, and the Pyrrhonists.Galen was concerned to combine philosophical thought with medical practice, as in his brief work "That the Best Physician is also a Philosopher" he took aspects from each group and combined them with his original thought.