 Some claim that songs of the Underground Railroad is an urban legend dating from the later 20th century and the beginning of the 21st.Skeptics claim that the legend has been picked up by credulous authors and published as fact without historical documentation.Some authors who believe the song held instructions for escaping slavery admit the ephemeral nature of oral history, often using such phrases as "supposed", "according to folklorists", and "gospelologists cite", to preface their statements.