The Formula of Reunion in 433 officially restored the peace of the churches but did not bring the Christological debate to an end.1 The resolution had been achieved only through delicate and difficult negotiations, and further diplomacy was required to maintain the fragile peace. The leaders of each party had the unenviable task of selling the agreement to their followers, some of whom were disinclined to accept any agreement with the opposing side. Some of the Easterners (so called because they came from the Roman diocese of Oriens or “East”), such as Theodoret, insisted that Cyril’s signing of the Formula of Reunion could only be interpreted as a departure from the position he had maintained earlier in the controversy, and they began pressing Cyril’s supporters with hard questions on this point. Cyril’s partisans then turned to the Alexandrian bishop to ask him to weigh in on the matter. On such person was Succensus, bishop of Diocaesarea in the province of Isauria, to whom Cyril penned two letters addressing the questions being posed by the Easterners and debated amongst his own followers.