Any classification is questionable because of its arbitrariness, however, it does not cease to have a certain usefulness in analyzing evolutions and comparisons.
Windelband proposed the following division for Greek philosophy:
Corresponding to the first philosophers
Identified with the time when philosophy concentrates on the problems of the city, specifically identified with the sophists and Socrates.
characterized by the doctrines of Democritus, Plato and Aristotle.
Corresponding to the doctrines of stoicism and epicureism