Constantine XI Palaiologos
If the latter identification is to be accepted, Bozhilov puts John Asen's birth at no earlier than 1444 and his death before 1449, when Demetrios Palaiologos ruled on Lemnos. He also dates the boy's portrait to after 1449, when Demetrios received half of the Morea as his possession from Emperor Constantine XI Palaiologos, including Kalavryta and the Mega Spelaion monastery.