The motivations behind Apollinarius of Laodicea’s Christology are debated by scholars, but it is safe to say that from the beginning he opposed any sort of dualist Christology.1 In Antioch, in whose ecclesiastical affairs Apollinarius was involved since the early 360s, two presbyters connected with the pro-Nicene Meletian faction, Diodore and Flavian, espoused a dyophysite Christology.2 Diodore became bishop of Tarsus in 378 and Flavian bishop of Antioch in 381. It seems that it was not until the late 370s that Apollinarius came into conflict with them, over issues that were as much as ecclesio-political as Christological. Fragments of Apollinarius’s writings against Diodore and Flavian are preserved in three later polemical treatises: Theodoret of Cyrrhus’s Eranistes, Leontius of Byzantium’s Adversus Fraudes Apollinaristarum, and the Doctrina Patrum de Incarnatione Verbi. These treatises mention a number of different Apollinarian sources for the fragments they preserve, but it is unclear if they refer to a single tract by Apollinarius or several. At least one of Apollinarius’s writings against Diodore was addressed to a certain Herakleion who is otherwise unknown (Fragments 117–120). No more than titles are known about the others, however many there were.