The classical art of memory (memoria), a private technique for aiding oratorical delivery (actio) in a public arena, clung on as a curious relic of a primarily oral culture in the medieval period – a time when the written word surpassed the spoken. Neglected in the public forum of the Middle Ages, the art was primarily used by monks as a compositional and meditative technique. The Dominican friars Albertus and Aquinas advocated the artificial memory, drawing on Cicero's conception of memoria as one of the three component parts of Prudence in De inventione (along with intelligentia and providentia). In theory, their advocacy of the use of the artificial memory supported the individual's use of memorable imagery to aid private devotional practice and prompt devout work in the world; in practice, in a wider sphere, it influenced the use of striking didactic imagery in late medieval and Renaissance Christian visual culture. Its influence has been identified in the design of visual alphabets, heraldic signs, stained glass windows, frescoes and friezes, figure poems, striking imagery on carved stone wall adornments, and, of course, emblem books. The underlying precepts of the Scholastic appropriation of the art of memory – ordered, coded associations based on repeated evocative imagery to instruct prudential behaviour – can also be identified in cultural practices and movements, such as the ars moriendi, danse macabre and memento mori traditions, in educational practices, such as the dissemination of popular and sacred history in spectacles, such as Corpus Christi processions, and even the composition of music and musical systems.
However, the Scholastic advocacy of Ciceronian artificial memory represents only one strand of transmission to later culture. Important also were the religio-philosophical writings of the Majorcan Franciscan missionary Ramon Lull. Lull's combinatorial art (ars combinatoria), rooted in Augustinian Platonism's conception of the presence of divine realities in the soul, sought to classify knowledge by breaking down ‘compound concepts into simple and irreducible notions’. In effect, using letters and symbols to represent these irreducible notions, which could be combined in various ways, Lull created an artificial universal language based upon the attributes of God (Dignitates Dei). Such a Christian scheme organised around the divine attributes or names of God has much in common with cabalist meditation in Jewish mysticism.