In this article, both Anaxagoras' theory of multiple worlds and the principles of his theory of matter are examined. It is argued that the five principles, which are set out explicitly in the extant fragments, (No Becoming, Indefinite Types, Universal Mixture, Predominance, and Infinite Divisibility) form a consistent set. Further, it is argued that the principle of Homoeomereity, which Anaxagoras attributes to Anaxagoras, is consistent with Anaxagoras' other principles and is likely to be a genuine principle of Anaxagoras' physics.