Medieval Christian theology ascertained that there are four Virtues: Fortitude, Justice, Temperance and Prudence. It is Prudence which is important as this was considered to be the place of memoria or memory. Within prudence, medieval scholars included memoria, intelligentia and providentia. Two works were of special significance as they drew excessively on these ideas - Albertus Magnus's De bono (IV, 2) and commentary on the De memoria et reminiscentia, and Thomas Aquinas's Summa Theologiae (H, ii, 49). Rossi[xii] notes that the discussions of memory in Albertus's De bono and the Summa Theologiae of Aquinas are explicitly derived from Aristotelian and pseudo-Ciceronian sources (pseudo in the sense that the Ad Herennium was considered to be by Cicero). Rossi quotes Albertus – “It is natural memory which helps us easily to remember things we have known or done in the past. Artificial memory is that memory which is constructed by means of the arrangement of places and images.' As in all the other arts, perfection in the art of memory is attained naturally, and since in our actions 'we are directed from the past towards the present and the future, and not vice versa', memory is presented, along with intelligence (intelligentia) and providence (providentia) as one of the three components of the virtue of Prudence.