 Beyond these explicit mentions, it is clear that Sherwood’s works were widely influential among logicians at the University of Paris in the second half of the 13th century. The most direct line of influence runs from William of Sherwood to his much better-known colleague Peter of Spain. It was for many years believed that Peter was the first person to translate Psellus’s text (Mullinger 1873, p. 176), prior to the rediscovery of Sherwood’s Introduction, which pre-dates Peter by two decades and which is closer to Psellus’s work. Peter’s Summary of Logic is clearly indebted to Sherwood. Kretzmann notes that “many of the features of the Summulae that made it far and away the most popular logic textbook in the Middle Ages seem quite plainly to have developed as modifications of more difficult discussions and less felicitous mnemonic devices in the Introductiones” (Kretzmann 1968, p. 6). On the other hand, Sherwood appears to have been influenced by Peter’s treatise on syncategorematic terms in writing his own; Kretzmann provides a summary of passages in Sherwood’s treatise which “can be read as allusions to positions taken by Peter” (1968, p. 7). Other influences can be found in Albert the Great, who used Sherwood’s notion of appellation rather than Peter of Spain’s (Kretzmann 1966, p. 5), and Thomas Aquinas, whose analysis of modal propositions follows Sherwood (Kretzmann 1966, p. 5; Uckelman 2008).