Well, Hell is a very specific object, because it is not really accessible, unspeakable, invisible… technically, some knew that there was an afterlife space where people would be rewarded according to their deeds/actions. And the Christian church which set up a series of rules/laws had some difficulties to enforce them. So first they promised the Paradise to the righteous and some sort of hell to the wicked. The problem is that the meaning of these words was not that clear.
So think about it? How can you talk about a place that is not accessible, not visible, not speakable… or to make long story short, that can only be attained by the dead from where you cannot return? Where stands any credibility here? Well, to talk about it, one needs to visit it…
So let’s see, in the Vth century Christendom … does it seem that unreasonable to visit the afterworld ?