In 1416 Emperor Manuel II Palaeologus wrote a letter to his spiritual fathers David and Damianos who resided in the Monastery of Vatopedi on Mout Athos. This hitherto unpublished letter accompanied an as yet unedited lengthy work Manuel composed in the form of a confession addressed to his aforementioned spiritual fathers on the occasion of his own recovery from a serious illness. The study comprises a critical edition of the letter preceded by extensive introduction examining the circumstances of the composition of these works and a palaeographical study of the letter, which survives in three 15th-century manuscripts and two later copies.