 Closely related to these problems was Aristotle’s doctrine of prime matter, which had controversial implications: as matter was eternal, so was the world, and therefore the Christian dogma of the creation of the world was untenable. Scholastic philosophers had long struggled with this subject during the Middle Ages, and the most interesting developments during the Renaissance were driven by the confrontation between Aristotelianism and Platonism. Plato, in the Timaeus, had clearly spoken of a God-creator, and once again his doctrines were adopted by authors anxious to establish a new philosophical foundation for Christianity. Bessarion (d. 1472), for example, admitted that according to Plato matter was eternal, but that he distinguished it clearly from the creator, who possesses a superior eternity. In similar fashion, Marsilio Ficino expressly described prime matter as created and therefore not subject to generation and corruption. Aristotelians were not always afraid, however, to argue for the eternity of the prime matter: Francesco Vimercato (1512–1569), in his posthumous De rerum principiis, is the most remarkable example. As late as the beginning of the seventeenth century, the debate continued: Cesare Crivellati composed a dialogue (1617) between Plato and Aristotle in which the master rebukes his unfaithful student for teaching such an impious doctrine. On the other hand, there were also authors who attempted to establish an accord between Plato and Aristotle on this sensitive issue: a good example is the De naturae philosophia seu de Platonis et Aristotelis consensione (1554) by Sebastian Fox Morcillo (1526–1560), in which the Spanish philosopher compares the doctrines of the Timaeus and the Physics, and emphasizes the limits of both in front of the perfection of religion.