 Plutarch is also familiar with Neo-Pythagorean and Aristotelian philosophies. Interest in both Pythagorean ideas and Aristotelianism were in vogue at the end of the 1st century BCE and during the 1st century CE, when Plutarch writes. There is a wave of Neo–Pythagorean treatises written at this time, such as those of ps–Archytas, Euryphamus, Theages (see Dillon 1977, 341–361, 1988b, 119–122, Centrone 1990), while Plutarch's contemporary Moderatus attempted to systematize Pythagorean ideas as background to Plato (he wrote a work Pythagorean Doctrines in many books; Stephanus Byzantius, s.v. Gadeira, Porphyry, Life of Pythagoras 48; Dillon 1977, 344–351). Aristotelian philosophy, on the other hand, was revived by Peripatetics and Platonists alike during this period. In the Peripatetic camp this is the time when Andronicus of Rhodes was active, being responsible for a complete edition of Aristotle's works at the end of the 1st century BCE, while Xenarchus of Seleukeia was critically engaged with Aristotle's physics. But already before them, Antiochus and Cicero had been well acquainted with Aristotle's works, the former arguing that Aristotle was in essential agreement with Plato, at least in ethical theory (Cicero, Academica I.17, De finibus V.12). Antiochus' students Aristo (of Alexandria) and Cratippus regarded themselves as Peripatetics (Index Academicorum col. 35.2-17 Dorandi), while the Platonust Eudorus did not hesitate to use Aristotle in order to identify Pythagorean metaphysical principles in Plato (Alexander, In Met. 58.25–59.8 with reference to Aristotle Metaphysics 988a8–17). Plutarch was familiar with several Aristotelian treatises from all periods of his writing career (cf. Adv. Col. 1115B-C) and, quite interestingly, he preserves numerous fragments from lost Aristotelian works (see Ross, Aristotelis Fragmenta Selecta, Karamanolis 2006, 89–92). Plutarch's attitude to Pythagoreanism and Aristotle is complex and sophisticated.  Plutarch's cosmic principles, the One and the Indefinite Dyad (De defectu oraculorum 428F-429A), allegedly found in the Timaeus, had long been considered Pythagorean in origin. Plutarch shows his familiarity with Pythagoreanism in the second (and rather cryptic) part of On the Generation of the Soul in Timaeus, where he seeks to explain the nature and role of numbers and ratios in the Timaeus making repeated references to Pythagoreans. Plutarch also integrates into Platonism other Pythagorean elements, such as number symbolism (De E 387F, De def. or. 429D-430B), abstinence from meat (On the Eating of Flesh; De esu carnium), and a belief in the rationality of animals (On the Cleverness of Animals, Beasts are Rational; Bruta Animalia Ratione Uti), probably because he considers them implied in, or compatible with, statements made in Plato (e.g. in the Phaedo, Timaeus). With regard to Aristotle, Plutarch is more cautious than Antiochus; he considers some of Aristotle's doctrines to be an articulation or development of Platonic philosophy (e.g. Aristotle's ethics, logic and science; see Teodorsson 1999), and espouses them as being Platonic (e.g. De virtute morali 442B-C, De an. procr. 1023E). However, he also criticizes Aristotle for contradicting Plato's presumed doctrines (e.g. on the Forms and on the constitution of the world; Adv. Col. 1114F-1115C; see Karamanolis 2006, 85–126).