Liberation of Constantinople - 1250 (Premysloides Dynasty)

Background
After Fall of Constantinople and with uncertain situation near Venice, Yahya al-Gabal proclaimed himself as "Sultan of Rum" (Roman Sultan), declared Roman Sultanate and ordered Nicean Empire to swear him loyality and convert to islam.

In that time, Hulegu Khan of Il Khanate was already known from his agents and informers about betrayal and conspiracies among many vassals and that most dangerous and strong conspiracy is among Seljuks.

When Nicea, Thessaloniky and other cities declared loyality to Emperor Romanos and called Yahya traitor and criminal, Yahya I declared war on these territories and mobilized his army. However, in that time, from Ancyr, about 10,000-strong Mongol cavalry army under personal command of Hulegu Khan, moved toward Constantinople, to punish traitors and conspirators.

Battle
Liberation of Constantinople was very short event. Hulegu Army arrived to Bospor in night of 20 January 1250. His army used vessels from locals, many bridges and dark night to cross Bosphor. In morning 21 January 1250, Mongols captured in surprise attack, Galata and passed through Golden Horn. During afternoon, Mongol horde breached gates and walls, flood Constantinople and killed every Seljuk Turk they met. About 25,000 Turks were killed in battle itself and 20,000, include Yahya and his commanders, captured.

Aftermath
Hulegu punishment was very familiar to each case when some Mongol vassal uprised against Mongol liege. Brutal, merciless and ruthless. Yahya al-Gabal was flayed, while all other captured were burned alive. Yahya commanders and Seljuk lords participating in rebellion, were buried alive.

Seljuks Fleet, previously stolen from Hulegu Khan, was recaptured and sent to Mongol ports.

Later, First Constantinople Conference, occured shortly after Liberation of Constantinople. Liberation of Constantinople, however, was only first step in revenge of Hulegu Khan. To prevent all other rebellions, Hulegu Khan ordered to destroy all Seljuk cities, kill all Seljuk adult men, divide Seljuk vassals territories among Roman Empire and Il Khanate, crucify every tenth woman and every fifth child.

With later purge in eastern vassalage, Il Khanate was stable by this bloodshed until collapse after Abaqa Khan death.