It is appropriate, though in an important way misleading, to open a discussion of Bonaventure's Itinerarium Mentis in Deum with an acknowledgement of his intellectual debts. ‘Bonaventure's work is regarded with good reason as the supreme example of mediaeval Augustinianism’, writes Grover Zinn, and in no work of Bonaventure's is this debt more manifest than in his Itinerarium. But if, as we will see, Bonaventure's Augustinianism is often filtered through the prism of an equally enthusiastic Augustinian of the twelfth century, Hugh of St Victor, the effect of Hugh's influence was to bring that Augustinianism into play with the other main stream of Christian Neoplatonism, the Dionysian. Zinn therefore adds: ‘This confluence of Augustinian and Dionysian materials in Hugh of St Victor's thought is most important for the development of theology, and especially in relation to Bonaventure.’

Having begun our discussion with extended reflections on these two great streams of Christian Neoplatonism, their convergence in Bonaventure gives him a pivotal importance for our discussion. But though it is appropriate to begin this chapter with a mention of Bonaventure's major sources, it is potentially misleading. For a reader of the Itinerarium, uninstructed in these and other, lesser sources, the most vivid impression will be of both the unity and coherence of thought, style and imagery and of the personal distinctiveness of Bonaventure's theology. Consequently, an analysis which did no more than to fragment this integrity into the multiplicity of its ‘influences’ – an effect of source-critical method which is always to be resisted – would miss the point, more particularly in this work than in many another, less integrated, text. Yet a compromise must be struck.