Early Christianity is a necessary phenomenon
of the 1st century AD. The emergence of imperial power in Rome and the new social rules it entailed demanded a religion that could give a religious blessing to the new social norms. The coexistence of many peoples and cultures in the Roman Empire encouraged religions that all cultures found acceptable.
If early Christianity hadn’t existed, another religion would have taken its place. The emperor’s cult was an attempt along these lines in Asia Minor. Because early Christianity was a necessary phenomenon of the early Roman Empire, it can, and must, be investigated as a historical phenomenon, beyond theological assumptions.