The last period of Byzantine history is provided with historical sources much better than the previous one. This is not surprising, because in the XIII-XV centuries. people wrote more than in the early Middle Ages, and what was written later is usually preserved better. It is to this time that the bulk of the unpublished works of Byzantine writers belong - many letters and speeches stored in various archives. On the contrary, archaeological materials, monuments of epigraphy, sphragistics, numismatics of the XIII-XV centuries. preserved in relatively small quantities and do not play a significant role in the study of late Byzantine history.