Soothsayers are fortune tellers, or people who claim to be able to predict the future. In Canto XX, Dante and Vergil encounter these souls, forced to walk with their heads forever facing backwards. Fortune-telling was considered a form of black magic or witchcraft, and was a form of heresy according to the Church. The punishment, like so many in Inferno, is cruel but in poetically just. Having spent their lives attempting to see the future, they must now always look back. Dante weeps to see these men contorted and tormented so.