In The Constancy and Development of the Christology of Theodoret of Cyrrhus Vasilije Vranic offers an assessment of the involvement of Theodoret of Cyrrhus in the Nestorian and Miaphysite controversies of the fifth century. Theodoret’s Christological language and concepts are examined in their historical contexts. The study is based on the comparison between the early period of Theodoret’s Christological output (Expositio rectae fidei and Refutation of the Twelve Anathemas) and his mature period (Eranistes). Theodoret’s Christology is ultimately vindicated and his position as a credible theologian who anticipated the definition of the Council of Chalcedon (AD 451) is assured, while proposing that challenges to the consistency of his Christology ought to be reconsidered.