The Neoplatonic extravagances which lay hidden in the school from the first came in his writings to a head, and merged in pure phantasy.
Erigena's contemporaries, and was certainly unorthodox enough to justify the condemnation which it subsequently received from Honorius III.; but its influence, together with that of the Pseudo-Dionysius, had a considerable share in developing the more emotional orthodox mysticism of the 12th and 13th centuries; and Neoplatonism (or Platonism received through a Neoplatonic tradition) remained a distinct element in medieval thought, though obscured in the period of mature scholasticism by the predominant influence of Aristotle.
The moral philosophy of Aquinas is Aristotelianism with a Neoplatonic tinge, interpreted and supplemented by a view of Christian dogma derived chiefly from Augustine.
Neoplatonic philosophy had been in the main content either to formulate the contradiction or to deny the reality of one of the opposing terms. And traces of Neoplatonic influence, more especially as regards their doctrine of the unreality of the material and sensible world, are to be found everywhere in the Christian philosophers of Alexandria, preventing or impeding their formulation of the problem of freedom in its full scope and urgency.
Under these teachers he became familiar with the Talmud and, what was probably more important for his own development, with the philosophical writings of Ibn Ezra and Maimonides, Levi ben Gerson, Hasdai Crescas, and other representatives of Jewish medieval thought, who aim at combining the traditional theology with ideas got from Aristotle and his Neoplatonic commentators.