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Some Christians argue that the earliest source of political federalism (or federalism in human institutions; in contrast to theological federalism) is the ecclesiastical federalism found in the Bible. They point to the structure of the early Christian Church as described (and prescribed, as believed by many) in the New Testament. In their arguments, this is particularly demonstrated in the Council of Jerusalem, described in Acts chapter 15, where the Apostles and elders gathered together to govern the Church; the Apostles being representatives of the universal Church, and elders being such for the local church. To this day, elements of federalism can be found in almost every Christian denomination, some more than others.

When was the latest source of political federalism according to Christians?
unanswerable