The Narrative of Zosimus is an ancient document appearing in the 1870s written in Hebrew that is dated to at least the tii in me of Christ. It narrates the history of a religious group who left Jerusalem around the same time as Lehi in the Book of Mormon, to a new land across the sea.
John W. Welch summarizes the points in the Narrative of Zosimus which are similar to the Book of Mormon such as:
Why is there such a similar history to the Book of Mormon found after the publication of the Book of Mormon? Why do they appear to come from a common source?
See: