Christianity blossomed into a major religion during the 4th Century. Emperor Constantine had become Emperor of the western part of the Roman territories in 312 and by 313 had signed the Edict of Milan making Christianity officially a legal religion. He eventually comes to rule the entirety of the Roman Empire and decides to move his capital to the more-Christian eastern region, marking the founding of the city that would eventually come to be known as Istanbul. After his pro-Jewish heir was overthrown (described by Roman Christians as an ‘act of God’), Emperor Theodosius bans paganism in 393 in response to the persistent invasions of the Germans from the west.
While Europe during the 4th century is marked by the consolidation of power and expansion of a singular religion, political power in Asia was being fractured and religious authority more divided. Civil war weakened the Chinese emperor in the early part of the century and tribal armies begin to rule northern China by 311. India, though flourishing economically, has broken into distinct political fragments. The Gupta empire becomes the dominant force in the country by 352 and continues to rule through the rest of the century. At the same time, Buddhism has moved from India through China and is beginning its take-over of the Korean peninsula. In 372, the King of Goguryeo has become a patron of Buddhism, solidifying its presence on the peninsula.