The Ecthesis Chronica implies she was the daughter of a holder of the military rank of protostrator, and Nicol notes there are chronological grounds against identifying her father with one Manuel Kantakouzenos who was sent on a diplomatic mission to Sultan Mehmet I in the winter of 1420–1421.
[1] A passage in the History of Chalkokondyles states that Theodora became the mistress of the protovestiarios of the court of Trebizond, an act of adultery which provoked her son, John IV, to murder the official then imprison his parents in the palace.
It may be the writer of this story has confused with an earlier affair between a member of the imperial dynasty of Trebizond and a protovestiarios, namely Manuel III, the father-in-law of Theodora.
On the contrary, the virtue, the piety, and the fidelity of Theodora are celebrated by her compatriot, the scholar Basilios Bessarion, in the three monodies he dedicated to his benefactress, and in a special discourse of consolation addressed to Alexios IV, devastated by the death of his beloved empress.
Last but not least, John IV himself, after his accession to the throne in 1429, paid homage to the virtues of his deceased mother in a chrysobull benefiting the convent she founded.