I originally read this story in German, but I'm pretty sure it is a translation from English. I have read it at around 2010, but the story was in a book already being older. I got it from a sale at a small price. I can remember some heavy wear on the book, so it might be from 2005 or earlier.
Please help me identify it, as I want to give it to a friend. Unfortunately, I can only remember some of the details.
In an alternate timeline Jesus was not betrayed by Judas, leading to him becoming emperor of the Roman Empire. The empire grows to great strength and a high technology level.
At the beginning of the story the empire is at a constant war with an American civilization, perhaps based on the Aztec or Mayan cultures. The European civilization never explored the American continents until the native civilization had grown too strong to conquer.
It is about a group of time travellers who are hit mid-travel and fall out of their travel at the time and near of Jesus workings (which they only find out after about one quarter of the story).
Thanks to some stolen uniforms and a matter-transformator they get into a nearby town and establish a base of operation. After some character development, tragedy, and so on they decide to visit Jesus. I don't know exactly what happens next, but in the end they are accused as wizards (because they made perfect copies of a coin when they arrived), some die and they decide to split up.
One of them is really disillusioned of what the future made of the Jesus he met, so he decides to change the timeline. He counts the silver coins remaining in his pockets and finds that he has 30 of them. He sees a guy leaving a house and approaches him with the words "You must be Judas, right?" (Story ends)