Do people who do not know about christianity go to hell?

lets say that back then christianity was only known to the romans and some other parts of the world. And it states that u need to believe in god to go to heaven and believing in other dieties send u to hell. but back then christianity was only known by a small part of the world, are you saying that people from other parts of the world are going to hell, THEY WERE NOT EVEN GIVEN A CHANCE TO LEARN ABOUT THE CHRISTIAN GOD, how are they not allowed into heaven, their whole lives they have been believing and were taught something different, and when their judgement day comes its like oh youve been believing something false all your life so youre going to hell. they did not know about christianity so how can they be condemned like that.