I have been frustrated by the following issue.
In the structure of the late roman empire, provinces were grouped into diocese, which were in turn grouped into praetorian prefectures.
The civilian and military administration of these units were separate, and followed the hierarchy.
land : province < diocese < praetorian prefecture < empire
civilian: corrector < vicarius < praetorian prefect (< emperor)
military: Dux < m. militum/c. r. militaris < emperor
I have read that the geographic divisions of the catholic church are leftovers from this system. For example, ecclesiastical provinces and diocese started off as their secular roman counterparts.
But in the church, diocese are grouped into provinces, not the other way around as used to be the case.
It seems to go like this:
parish priest < bishop < metropolitan bishop < patriarch < emperor
My intuition would suggest that bishops oversaw provinces, not diocese. And that metropolitan bishops governed the church from diocesan capitals, not provincial capitals as I have seen written.
It seems clear that the church was not organized in a way directly corresponding to the rest of the state. For example, the patriarchates do not correspond to praetorian prefectures, despite their similar number and hierarchical place.
So anyway, what exactly is going on here?