If Dusan lives long enough to make that peace...
That was a cliffhanger: the narration stopped in November while Dusan died/got poisoned in December. I look forward to the next update.
From a certain POV they will get. Peace with Serbia means that part of the serbian silver will be exported via Thessaloniki. The Serbian elites needed luxury textiles and spices in return for bullion. The Despotate can provide both. The Sardinian mines will be exhausted in 1365 and it will kickstart or at least exacerbate a silver famine. Said famine got much worse when the Ottomans captured the serbian and bosnian mines. Then, it seems that Longobucco continued to produce til the late 18th century, even if it was much less productive than the central european mines.Though is the peace a white peace? Feels like the Lascarids could have gotten some money from Stefan, the "I got silver mines to fund me invading everyone" guy.
In TTLthere is a very good chance that the balkan silver mines will continue to be part of the christian trade network and the Despotate will be in a good place to become an equivalent of OTL Venice in the export of bullion to the Indian Ocean via Egypt. If such development takes place, then we are talking about incredible wealth: an almost monopoly on spices til the Portuguese reach the Indian Ocean, then a collapse to a third of the volume at the beginning of the 16th century and a recovery after the 1540s with a duopoly until the Dutch reach the Indies at the late 16th century.
Manuel Kantakouzenos had taken less than well to Gattilusio showing up in Mytiline with imperial order to give Lesbos over to a Genoese former pirate. Francesco was hardly the kind of man to be deterred by a mere Greek's refusal or the odds. Perhaps he should have as Manuel would prove a much tougher customer than his father crushing Francesco small squadron and killing him.
A pity that the capable Manuel did not succeed his father. He seems to have been much more capable than both Palaiologos and his brother Matthew. It seems that there are three possibilities now:
a) Manuel stays in his rich little appanage after an affirmation by Ioannis. He gets rich and maintains his strong garrison of 500 cavalry and 1000 infantry. The Maritime Powers leave him be, since it will be expensive to capture Lesvos.
b) He is closer to his brother Matthew than in OTL and doesn't have the Principality of Achaea next door. With his small fleet and army he can have reasonable success in Western Thrace. Even in 1356, the ability of Constantinople to project power west of the Evros river will be very limited. The cities there will be looking for a protector. It can be Manuel or more likely Dusan or even Alexandros.
c) If Ioannis is smart - which I doubt, he will reach an accord with Manuel to have his army and fleet attack Gallipoli early on. Manuel and the rest of the Byzantine islands, can produce an equivalent of the Savoyard Campaign.
If he lives, he will be an excellent buffer against the Ottomans and might conquer most of Thrace during his lifetime. Since he is the same ruler as in OTL, he will still oversee a decentralized state that will break when he dies.If Dusan lives long enough to make that peace...