Constantine legalized Christianity, moving it from a persecuted cult to the favored religion of the state.
Germanic tribes crossed the Rhine and Danube, while the Sassanid Persians pressured the East. The Roman Empire from Severus to Constantine
After Diocletian’s retirement, the Tetrarchy dissolved into civil war. Out of the smoke emerged . Following his victory at the Battle of the Milvian Bridge in 312 AD—where he claimed to have seen a vision of a cross in the sky—Constantine fundamentally altered the course of Western civilization. Constantine legalized Christianity