Historically, Thessaloniki is one of the most important cities in Europe, though it’s probably never been quite as prominent as its importance should have warranted because it’s generally would up being overshadowed somehow. Founded in the fourth century BC by Macedonian King Cassander, it rose in stature to become the most important city in Macedon…shortly before the Romans showed up. It became an important Roman city…because it was a way point on the main route from Rome to Byzantium. When Diocletian divided the Roman Empire into the Tetrarchy in the third century, it became one of the capital cities of the empire under eastern Emperor Galerius…and then Constantine ended the Tetrarchy and established a new eastern capital, Constantinople. It was the “second city” of the Byzantine Empire. Today it’s the second largest city in Greece. You get the idea.
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The Foreign Exchanges Companion 
1) If you haven’t read Leon Sciaky’s _Farewell to Salonica_, go and get it and read it. I promise you will like this book.
2) The great Venetian advantage: at this point they had complete command of the sea. (They had sunk the entire Ottoman fleet in 1419, wrecking it so completely that no Sultan bothered building another one until Mehmet in 1452-3.)
The great Venetian disadvantage: they didn’t really *want* Thessaloniki. They just wanted to sell it to Murad for a decent price. They were happy to pick up port cities and islands all over the eastern Mediterranean, when they were useful. Thessaloniki wasn’t. They couldn’t use it for trade while the Ottomans were hostile, and they didn’t really need it as a stopover point when Constantinople was just a few days’ sail west.
If the Venetians had really cared about Thessaloniki, they could have held it pretty much forever. But it would have been expensive, and Venice was always about cost-benefit calculations. Basically Murad outstubborned them.
3) That said, the experience seems to have left both sides bruised, and neither eager for a rematch. Maintaining the siege had been expensive for the Ottomans too, and they’d won little more than a pile of ruins. It would be 35 years before another Sultan was willing to throw down with Venice.
Doug M.