The second part of the introduction to the Doctrina Iacobi for Czech readers argues that the end of the passage concerning the false prophet coming with Saracens is a later interpolation. It proposes to see the work as a product of successive additions to and reworking of an original anthology of Old Testament citations.
The almost definitive version of the Doctrina (without the narrative prologue) is not an unequivocal source for the forced baptism of all Jews under Heraclius and could be dated to the end of the 7th or the beginning of the 8th century.