The metropolitans of Seleucia-Ctesiphon for the fourth century comprise Papa, Simeon bar Sabbae, Shahdost, Barbashmin followed by a long vacancy, Tomarsa, Qayuma, and Isaac. The parallel Sassanids were Sapor II (309-379), Ardashir II (379-83), Sapor III (383-88), Bahram IV (388-99) and Yezdegerd I (399-420).
The list of catholici is preserved in a number of different writers: PsEN (c. s. x), ChrS (c. 1036), Mari (c. 1150), PsED (c. 1260), BarH (1286), Amri (c. 1350), Sliba (c. 1350), and others.
The chronology has already been studied by G. Westphal in connection with his investigation of the sources and reliability of Mari, Amri and Sliba. He bases his dates principally on the Syriac acts of the Persian martyrs, but, as the present paper attempts to prove, this cannot be done: we must work the other way around, settle first the succession of the catholici and then turn to the acts. Furthermore, since the publication of his excellent work, the very valuable ChrS has been discovered and a critical edition of PsEN has appeared.