“…Having spent the first fifteen years of his episcopate writing extensive commentaries on Scripture, from 429 onward Cyril turned his enormous learning and talent for penning and distributing polemic tracts to the development of doctrinal orthodoxy after he sensed that the new ideas coming out of Constantinople threatened the very core of the Christian doctrines of Incarnation and salvation. The three treatises here translated into English for the first time all belong to the period around the ecumenical council. …”