Conclusion of Before European Hegemony

The book has come to a conclusion and it traced the rise of a world system from the end of the twelfth to the beginning of the fourteenth century. It goes on to say that the system was not global, since it did not include the Americas or Australia. Although it still represented a system larger than the world has previously known. The system was extremely uneven, only integrating into world cities elevated above rural areas and open stretches. This was not a unique situation for the thirteenth century. This thirteenth century international trade was substantially more complex in organization, greater in volume, and more sophisticated in evolution than any thing else the world so far has seen. It wasnt until the development of the steamship in the nineteenth century did the shape of the world system dramatically alter. No particular culture seemed to dominate the thirteenth century. There wasn't any dominate religion either or values that was upheld in the thirteenth century.
I find it interesting that there was so much diversity in the thirteenth century to the point that there was no definite cultural trend that dominated the century. I wouldn't expect people to be so opinionated and diverse and to publicly show that around this time.
My question is why do you think there wasn't a dominate religion during this century? What aspects of this era could account for that?