 His "Contra adversarium perfectionis christianae" of c. 1269, in support of William of St Amour, argued that extreme emphasis on poverty contradicted the Aristotelian doctrine of the mean and undermined the basis of pastoral work.It provoked replies from Thomas Aquinas and Bonaventure.From the Franciscan side, Bonaventure wrote "Apologia pauperum", and John Peckham wrote his "Tractatus pauperis".