During the first season of Civilization V, only one religion was founded.
Holy Frenchism was founded in the French capital of Paris, and was known to be suited for desert civilization, such as France and Venice. It quickly spread throughout the French empire, and eventually spread to Venice. It also expanded to the Ethiopian city of Adwa, owned by the game AI, and to the Shoshone city of Novenice Dogesu.
Since Holy Frenchism was the only religion founded in the first season, there were never really any conflicts at all.