Christianity has been reframed in the context of Roman militarism from its very beginning as an official religion. It's in the myth itself, Constantine converting at the Milvian Bridge. The end result being a system of beliefs that's both socially conscious and allows for violence on behalf of the State. Pre-Christian religion in the Empire was weaker in that sense, as it was mostly concerned with ritualizing arbitrary decisions. It was a good fit for Germanic warriors trying to upgrade to Late Roman land-owners.