One of the earliest images of Jesus,
from St. Callisto catacomb in Rome (ca. 250 AD)
Around the time of the beginning of the Roman Empire, a new religion began among the Jews living in Israel: Christianity. Christianity tapped into a lot of ideas that people were starting to think about more at this time, like the idea of the afterlife, the separation of church and state, and the separation of the soul from the body. Partly because of this, and partly because of good organizational skills, Christianity was a big success, and quickly spread all over the Roman Empire, and also (though not as much) into the Parthian Empire and to the Goths and other Germanic people. At first there was a lot of trouble. Many Romans and many Parthians hated the Christians and sometimes Christians were killed. But by 312 AD, three hundred years later, there was a Christian Roman Emperor, and a hundred years after that it was illegal NOT to be a Christian. This is the story of how Christianity got to be so important.