Your church became the state church of the Roman Republic well before any of these, Campion, and tgat is why I called it the original State Church.
Edict of Thessalonica
“The Edict of Thessalonica, also known as Cunctos populos, was issued in 380 AD. It ordered all subjects of the Roman Empire to profess the faith of the bishops of Rome and Alexandria. The edict made Christianity the state religion of the Roman Empire.[1]”
http://en.wikipedia.org/wiki/Edict_of_Thessalonica