In an era of great human discoveries arose a compulsive desire to learn of man's origins and place in the scheme of the universe. People aimlessly searched for one to guide them with wisdom on the right path, the path away from suffering. In the West, in the small country of Israel, such a man arose. But before him, another in the East came and went, a man of great spiritual clarity and charisma. Both men faded away, but they left legacies that changed the very fabric of history on opposite hemispheres. Both men had very similar teachings, and they spread across the globe almost simultaniously, changing the hearts of all whose paths crossed. .
In the dominating land of Rome to the west, a land of mostly athiest and diversibly accepting roots, an emperor arose, Constantanople, who admited his faith to being overtaken by the "holy light" of Jesus. It wasnt long before the church became a vital part in the political system of Rome. And as History tells time and time again, when the chruch and state intervine, collapse likely occurs. With massive sepperation between the Roman provinces, and economic and religeos unrest, the fall came to be. Christianity teaches the importance of the church over anything else, therefor new believers would go openly seek out a "Godless" locale needing the fullfillment of a church. In this church, new believers would learn that they too also must spread the word of God through the same methods - building a church and converting more people. The more people you convert in Christianity, the more rewards you will have in heaven. So take a man like Constotine who holds an entire empire under his belt, and you can easily understand why this man wants to do some major converting. Caravans and soldiers off to war were especially susceptable; they would learn of the new religion in forign lands, then see the need to spread it whence returning to their hometown. Therefor the Christian "franchize" came to be.
