Christianity is very different from the pagan religions of earlier civilizations like ancient Greece. But it was received by most Roman citizens as a cult in which people practiced cannibalism and infanticide and other despicable acts. Although it was received this way, the early Christians withstood the persecutions inflicted upon them.
Christianity teaches that there is one God, while most pagan religions taught the worshiping of many gods: gods of the hearth, Olympian gods, etc. Along with the belief of one God, the Bible inclines it’s followers to turn the other cheek when struck, and that revenge is the Lord’s. The ancient Greeks believed in a system of revenge carried out by the victim or a relation of the victim. “Love your enemies” is a well known phrase from the Bible that contradicts the Greek’s revenge belief.
There are a few similarities as well between the Christianity and the teachings of the great thinkers of ancient Greece. Hesiod, for one, implored that bribing is wrong, and that one should work from early in the morning to dusk, not to laze around. The Bible warns against bribery and it teaches something similar to getting up early to work, so that destruction may not come upon you. Plato, Socrates, and Aristotle each had a couple things they taught that are similarly taught in the Bible, mostly concerning how one should live virtuously.
We can conclude that the Bible and pagan religions and philosophers shared some similarities, but are separated widely by many differences. Some people in Rome “converted” to Christianity simply because it was, to them, a blend of all the other philosophies like neo-pythagoreanism and neo-platonism, stoicism, and others. They were searching for something that concerned physical and spiritual contentedness. But Roman authorities weeded out many who weren’t true followers through torture or other methods.