 The idea that certain knowledge requires divine illumination enjoyed steady popularity from antiquity to late thirteenth century. The philosophical appeal of the view is familiar from Plato’s epistemology, and Augustine’s remarks popularized it among early medieval theologians. These remarks do not constitute a detailed theory of how illumination takes place, but in the mid-thirteenth century prominent authors such as Bonaventure and Matthew of Aquasparta developed a systematic defence of it. At the influence of Aristotelian epistemological theory, the theory of divine illumination came under pressure and it was both attacked and defended from many perspectives, e.g. by explaining illumination by separating the agent intellect from individual human beings and identifying it with God. Olivi was the first Franciscan author to launch a heavy critique of the Augustinian idea that universal cognition requires divine illumination. He presents (in Summa I, q. 2) a thorough criticism of the reasons that were used to defend it, and although he ends up accepting the position, he emphasizes that the theory must be carefully formulated so that it takes into account the shortcomings he has pointed in it—all of which can be taken to qualify it to the brink of rejection (see the entry on  divine illumination).  After all, one of the conditions that he sets for the true theory is that “it does not take away the possibility of true and certain judgement and understanding” (Summa I, q. 2, p. 510) from the human mind, and in another context he argues that the acts of understanding originate in the human intellect (Summa II q. 74; Caldera 2010, pp. 235–36).