‘There is no difference between affectio and affectus, except that Cicero liked the former and Quintilian the latter.’ 1 Thus Erasmus of Rotterdam, the prolific and widely influential Dutch humanist, reflects upon the relationship between two key Latin emotion terms in a 1530 letter to his friend Peter Gilles. The letter to Gilles was written in the context of the publication of one of several apologiae Erasmus wrote in defence of one of his most important works, the very first printed edition of the Greek New Testament with a fresh Latin translation in parallel columns (originally published in 1516 and revised in 1519, 1522, 1527, and 1535). The letter itself contains a defense of the use of affectus in his Latin translation of the New Testament, a choice that had come under attack by the Flemish Franciscan Francis Titelmans in a 1529 work criticizing Erasmus’s Novum Testamentum. 2 The Vulgate does not use affectus in the New Testament, while Erasmus uses it over a dozen times, and so a Vulgate purist like Titelmans would have had ample opportunity for criticism. 3 Moreover, the fact that Erasmus never follows the Vulgate when it reads either affectio (3 times) or passio (18 times), while he otherwise retains some 60% of the Vulgate’s words overall in the 1535 edition (per de Jonge 4 ), indicates that Erasmus embraced a different emotional lexicon when compared with his predecessor(s). 5 It also belies his claim that there is no difference (nihil interest) between affectio and affectus.