Complex sentence: That synod agreed that Toledo was the metropolitan of the whole province, seizing that title from the episcopal seat at Cartagena-that agreement was then endorsed by the king in a decree of 23 October 610.
Split into simpler sentences: That synod agreed that Toledo was the metropolitan of the whole province, seizing that title from the episcopal seat at Cartagena. This declaration was endorsed by the king in a decree of 23 October 610.