Constantinople wouldn't need to be taken back from the Turks if the Catholic Venetians hadn't treacherously sacked the city in the 4th Crusade in 1204. The Byzantine emperor and his administration had opened the gates, as they always had, to allow the Crusaders to rest and replenish themselves before continuing on to Jerusalem.

The Byzantines didn't know that the Venetians had cut a deal with the Crusaders in exchange for the passage fee: this time, sack and deliver the city into Catholic hands and we'll call it even. The emperor's government wasn't expecting the treachery, so they were caught completely unawares by those they considered FELLOW-CHRISTIANS. They were compelled to flee to Nicaea to keep from getting captured and killed.

The Byzantine emperor and his court maintained a government in exile for the next 58 years before they could mount a recapture. In the interim, the Venetians flooded the city with Catholic clergy and forcibly rebaptized its Orthodox citizenry into Catholicism.

Upon its recapture, the emperor allowed its converted population the choice of recoversion back to Orthodoxy or leaving. Those who left, moved up to the Bessarabian area of Romania and were known as the Uniates or Greek Catholics. The city, however, was done. Its treasures had been hauled away to grace the palazzos of Venice and the city never recovered.

Before we talk about forcing the Turks to do anything, let's talk about compelling the Venetians to give back the city's treasures. While we're at it, we can talk to the French, too, since Napoleon captured Venice in 1804 and used the loot (along with what he got from the sale of Louisiana the previous year), to march his army into central Europe to abolish the Holy Roman Empire in 1805. They'll need to return their share of the stolen treasures of the Great City, too.

Edit: in fact, if we want to get down to the nitty-gritty, we'll have to undo the resumption of western trade with Asia, the Renaissance, the Reformation, and the Industrial Revolution, as well, since the vast hoard of loot pillaged from Constantinople was responsible for financing Venice's rise as a banking center (if: "it takes money to make money"...what do you think they were using as capital in order to make money??), their venture into long-distance Silk Road trade, and all the intellectual, artistic, spiritual and technological spinoffs that came with a moneyed economy.

Constantinople wouldn't need to be taken back from the Turks if the Catholic Venetians hadn't treacherously sacked the city in the 4th Crusade in 1204. The Byzantine emperor and his administration had opened the gates, as they always had, to allow the Crusaders to rest and replenish themselves before continuing on to Jerusalem.

The Byzantines didn't know that the Venetians had cut a deal with the Crusaders in exchange for the passage fee: this time, sack and deliver the city into Catholic hands and we'll call it even. The emperor's government wasn't expecting the treachery, so they were caught completely unawares by those they considered FELLOW-CHRISTIANS. They were compelled to flee to Nicaea to keep from getting captured and killed.

The Byzantine emperor and his court maintained a government in exile for the next 58 years before they could mount a recapture. In the interim, the Venetians flooded the city with Catholic clergy and forcibly rebaptized its Orthodox citizenry into Catholicism.

Upon its recapture, the emperor allowed its converted population the choice of recoversion back to Orthodoxy or leaving. Those who left, moved up to the Bessarabian area of Romania and were known as the Uniates or Greek Catholics. The city, however, was done. Its treasures had been hauled away to grace the palazzos of Venice and the city never recovered.

Before we talk about forcing the Turks to do anything, let's talk about compelling the Venetians to give back the city's treasures. While we're at it, we can talk to the French, too, since Napoleon captured Venice in 1804 and used the loot (along with what he got from the sale of Louisiana the previous year), to march his army into central Europe by abolishing the Holy Roman Empire the next year, in 1805 into returning the stolen treasures of the Great City.