Although the “letter” is included as a discrete unit in the Septuagint, there is no evidence of it ever having been canonical in the Masoretic tradition.

The earliest evidence we have of the question of its canonicity arising in Christian tradition is in the work of Origen of Alexandria, as reported by Eusebius in his Church History. Origen listed Lamentations and the Letter of Jeremiah as one unit with the Book of Jeremiah proper, among “the canonical books as the Hebrews have handed them down,” though scholars agree that this was surely a slip.