Gerard of Siena (c. 1295 – d. 1336) was a Tuscan student of Giles of Rome at the University of Paris who opposed usury.G. (2016). The Idea of a Moral Economy: Gerard of Siena on Usury, Restitution, and Prescription. United Kingdom: University of Toronto Press.Theological Quodlibeta in the Middle Ages. (2006). Netherlands: Brill. p. 557Augustiniana. (2001). Belgium: Augustijns Historisch Instituut.. p. 229 He lectured on Peter Lombard's Sentences.The Cambridge History of Medieval Philosophy. (2010). United Kingdom: Cambridge University Press. p. 872 References