Peripatetics in scholarly activities such as the exposition of Plato's doctrines and the explanation of his dialogues; on the other hand they attempted to develop the Platonic theories systematically. In so far as it was subject in this to the influence of neopythagoreanism, it was of considerable importance in preparing the way for neoplatonism. The most important of the middle Platonists was Plutarch (45–120), who also won fame as an historian. Although he was a Platonist, he was open to the influence of the Peripatetics, and even, in some details, to the Stoics, despite his polemics against their principles; he absolutely rejected only Epicureanism. In opposition to Stoic materialism and Epicurean "atheism," he cherished a pure idea of God that was more in accordance with Plato. Nevertheless, he adopted a second principle in order to explain the constitution of the physical world. This principle he sought not in any indeterminate matter, but in the evil world-soul which had from the beginning been bound up with matter, but in the creation was filled with reason and arranged by it. Thus it was transformed into the divine soul of the world, but continued to operate as the source of all evil. He elevated God above the finite world, but he believed that God comes to our aid by direct revelations; this enabled Plutarch to justify popular belief in prophecy. The gods of popular religion are merely different names for one and the same divine Being and the powers that serve them. Daemons were for him agents of God's influence on the world. Plutarch defended freedom of the will and the immortality of the soul. Platonic-Peripatetic ethics were upheld by Plutarch against the opposing theories of the Stoics and Epicureans. Among later middle Platonists there were Theon of Smyrna, who wrote a mathematical introduction to Plato, and Gaius (2nd century) who was a teacher of Platonist philosophy. His pupil, Albinus, wrote an account of his lectures, of which we possess the introduction. Around the same time, Alcinous wrote an extant treatise on Platonism, in which he postulated three principles: the first God, the ideas, which are regarded as thoughts of this "first God", and matter. Apuleius (c. 125), a popular writer, expounded an eclectic Platonism in his books On the God of Socrates and On Plato and his Doctrine, which are written in Latin. Maximus of Tyre (c. 180), like Plutarch, endeavoured to