Despot Constantine

from the Wikipedia page of his wife, Kera Tamara:

The first husband of Kera Tamara was despot Constantine. According to one theory he was the despot of Velbazhd Constantine Dragash whose daughter Helena Dragash married the Byzantine Emperor Manuel II and became mother of the last Byzantine Emperor Constantine XI. However, that theory has been dismissed by the historians because in 1371 Kera Tamara was already a widow while Constantine Dragash died in 1395. Therefore, despot Constantine who was depicted in the Tetraevangelia of Ivan Alexander next to the Bulgarian princess was another man.