Events leading up to the siege
In 1453, Mehmed II wanted to restore his father's (Murad II) dreams of taking Constantinople, and had been preparing a sizeable amount of soldiers he had been preparing and stopped in Edirne the reasons of which are unclear. His second cousin Orhan Çelebi, had initiated a coup and took Mehmed II prisoner
But due to and incompetence/treason in the high-ranking ottoman officials, Constantine XI Palaiologos found out about the plans to siege Constantinople and that Mehmed II was taken prisoner.
Alliances secured by Constantine XI Palaiologos
He sent letters to The Papal States, Knights Hospitaller, Albania, and the crown of Aragon. After securing alliances, Constantine went into the surrounding ottoman country recruiting orthodox Christians and raiding Ottomans camps pushing from the east, while simultaneously Skanderbeg was advancing to Edirne from the west, Hunyadi pushing from the north, and the knights hospitaller pushing from the south.
The knight's campaign from the south
The knight's first plan of action was to take Ephesus, but a regional Turkish army was sent to repel them but was soundly defeated at the Second Battle of the Masts (1453). They were almost going to completely abandon the Byzantines’ plan but would be saved by pure luck as they made their way towards Gallipoli troops had been redirected from that city to defend against Hunyadi and the gates were left open. The knights simply walked in.
Byzantine campaign
Although the Basileus had the advantage, he didn't have it by much very much, contemporary sources claim he only had 4,500 men, while others insisted they had hired Mercenaries from the area. They then surrounded Adrianople, with Constantine himself setting up his own camp directly across from the ottoman imperial palace.
| Siege of Adrianople (1453) | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Part of the Byzantine Reconquest of Thessaloniki | |||||||||
| |||||||||
| Belligerents | |||||||||
 Byzantine Empire Knights Hospitaller Papal States Aragon Albania Kingdom of Hungary |
 Ottoman Empire | ||||||||
| Commanders and leaders | |||||||||
|
Constantine XI PalaiologosJohn Hunyadi Fruzhin Ferdinand II of AragonSkanderbegJean de Lastic |
Mehmed II Orhan Çelebi † | ||||||||
| Strength | |||||||||
|
4,500-6000 Byzantines 20,000-21,000 Eastern Crusader Infantry |
Total strength 40,000 Sizeable garrison 400 elite Janissaries | ||||||||
| Casualties and losses | |||||||||
| 3,000-4,000 | Unknown, garrison killed and 10,000+ inhabitants spared | ||||||||