The so-called. ‘Christianization’ of Aristotle in the Middle Ages and in particular by Thomas Aquinas remains a vexed debate. A case by case study seems to be a fruitful approach. One of these cases concerns Aristotle’s definition of the soul in De anima II, 1(412b10-25). Applying this philosophical claim to the theological question Utrum Christus fuerit homo in triduo mortis seems to be not without difficulty, as St. Thomas’ frequent treatments of this question show. In this paper I analyze these texts and show how Aquinas on multiple occasions follows De anima II, 1 and similar texts of Aristotle and defends a robust Aristotelian position, even in light of the significance of his recovery of Greek Church Fathers.