How might our world be different today had Constantine never existed?

If Constantine had not existed Christians might still be persecuted and the Roman Catholic Church would never have come into existence.

Constantine is very important in the world history by the changes he made towards the Christianity and how he set up the scene for its progress. If it wasn't for him, the Christianity might have never been legalized, and to become the dominant religion in Europe, and afterwards in the Americas, and parts of Africa. Since the Christianity has had huge effect in the political sphere in Europe, and it is a big global player even nowadays, the world would for sure be a much different place if it never spread and gained power and followers. Maybe the paganism would have existed on a large scale, maybe another religion and its principles and morals would have become dominant ans shape the world, we can only guess, but it is sure that it was not going ot be the same.