David of Trebizond was the last emperor of Trebizond, a Byzantine successor state on the Black Sea. He came to the throne in 1459 after the death of his brother John IV and attempted to secure allies against the expanding Ottoman Empire. Mehmed II besieged Trebizond in 1461, and David surrendered after receiving assurances.
Accused two years later of maintaining dangerous correspondence, he and most of his sons were executed in Constantinople, ending the male imperial line. His motives at surrender are often interpreted through the tension between heroic resistance and responsibility for a civilian population.
In Dorothy Dunnett’s The Spring of the Ram, in 1461, Nicholas pursues Catherine de Charetty and the Genoese adventurer Pagano Doria from Florence towards Trebizond while also trying to establish a Black Sea trading venture.