As the very last land of the Roman Empire this siege has intrigued me, sadly the information that I can find doesn't even fill half a page. Would anyone be able to tell me more about this? or perhaps recommend a source that could tell me more? I'd also be very interested to hear about Graitzas Palaiologos, the commander of the garrison who went on to serve as a Venetian general.
This episode was part of what you could perhaps call the Byzantine Empire's epilogue after the fall of Constantinople in 1453. Following the siege there was still a Byzantine rump state in Greece. This was the Despotate of the Morea, a semi-autonomous appanage of the empire that was ruled by junior members of the royal family, the Palaiologoi. The Despotate encompassed most of the Peloponnese and was ruled by Thomas and Demetrius Palaiologos, two brothers of Constantine, the last emperor.
When Constantinople fell a revolt broke out against the ruling despots in the Morea. The rebels were tired of the brothers' incompetent rule and resolved to extinguish the last scions of the Palaiologoi. Sultan Mehmet II did not want a new rebel regime in the Morea and was happier with propping up the old government as a vassal state. An Ottoman force entered the peninsula in December 1453 and eliminated the insurgency. The brothers were allowed to continue as vassal rulers in exchange for tribute.
But Thomas and Demetrius proved incapable of governing effectively. The Morea slid further into anarchy and they began to miss tribute payments. It didn't help that Thomas was intriguing with the Pope to try and get a Christian army to come and oppose Ottoman rule. Eventually Mehmet got tired of all this and in Spring 1458 personally led an expedition to restore order.
There was little meaningful resistance and the episode ended with the northwest of the peninsula being put under direct Ottoman rule. The brothers were firmly chastised but even this wasn't sufficient to end their quarreling. Thomas maintained hope that the Pope would send him the aid he had been asking for. Demetrius decided to appeal to Mehmet for help against his brother's scheming.
By this time Mehmet had had enough. He arrived in Corinth in May of 1460 to finally put an end to all this. Demetrius gave himself up while Thomas fled to Corfu. Almost the entire peninsula fell without a fight. By autumn everything except the castle of Salmeniko had surrendered. The castle's garrison, under Graitzas Palaiologos, held out for an impressively long time against impossible odds. In July 1461 he finally abandoned the cause, made for a Venetian controlled port, and entered the service of the Serene Republic.
Graitzas was the Morea's last defender. He is an obscure figure and we don't know much about him outside of this event. However, he does represent the last element of Palaiologoi resistance to Ottoman rule in the midst of an otherwise unopposed final conquest.
Can Despotate of Morea even be considered as Roman Empire? Hell, even empire?