The heresy of Nestorianism, which held that Jesus was 2 separate persons, began in this Byzantine capital
The christological question then arose as to how Jesus Christ could be 
both... [DOC] [TLE] Council of Ephesus - Wikipedia [PAR] The Council of Ephesus was a council of Christian bishops convened in Ephesus 
in AD 431 by .... Cyril argued that Nestorianism split Jesus in half and denied that 
he was ... Cyril appealed to Pope Celestine I, charging Nestorius with heresy.