Can two semantic theories belonging to very different periods of time be compared? And if so, what can be gained from such an enterprise? In the following, we will consider the case of Anton Marty's (1847-1914) semantics of names and the medieval theory of supposition. The tertium comparationis is offered by the fact that Marty is making use of the distinction between suppositio materialis and formalis, a distinction that is found in a few late medieval logicians such as William of Sherwood, Walter Burley and John Wyclif and which had a certain success in post-medieval scholastic. Although the three authors mentioned do not describe formal supposition in exactly the same way, they do describe the same notion. Insofar as Sherwood can be considered as emblematic of the medieval position, we chose his Introductiones in logicam, which Marty may have known at least partly through Carl Prantl's Geschichte der Logik im Abendlande, as a basis for comparing Marty's semantics with the medieval theory of supposition. Whatever role Prantl may have played, Marty's master, Franz Brentano, who wrote himself a history of medieval philosophy, certainly also contributed to his knowledge of medieval thought. It is not our aim to discuss at length the question of Marty's sources, nor do we want to compare the use of the notion of suppositio in Marty, Brentano and, say, Tarski. Rather, we want to focus on Marty and consider Sherwood's definitions of significatio, suppositio and appellatio as points of reference or terms of comparison. Thus, we will begin with some remarks on the two passages in which Marty uses supposition theory; in a second step, we will present some of Sherwood's basic semantic notions and Marty's semantics of names; finally, we will attempt to draw some comparative conclusions.