This letter may be dated in February 431. Celestine and Cyril had written to John of Antioch in relation to the condemnation of Nestorius by the western bishops at Rome in August 430. Theodoret was at Antioch on the arrival of these letters and hence additional probability is given to the theory that he wrote the reply referred to in the preceding note. Then came the publication of Cyril’s chapter or anathemas which Theodoret undertook to refute. Letter CL. is prefixed to his remarks on them.