There were several factors that caused the decline of the Byzantine Empire. It was a decline that last longer than the Western Roman Empire. It last about 500 years.
- The Fourth Crusade which sacked Byzantium, and reduced Imperial power to the Nicaean Empire, Trebizond and Epirus.
- The rise of Islam, made the Latin Church decline in its power over the empire
- A series of societal infighting also weakened the Byzantine Empire's military power.
- Another possible explanation for the disintegration of the Byzantine Empire is the permanent settlement of Anatolia by the Seljuks, a Turkish people between the 11th – 13th century.
- The arrival of the Seljuk Turks led to the rise of the Ottomans, warriors that followed the Noble (Bey) Osman I. Attempts by the Byzantine Emperors to drive back the Ottomans yielded little short term success – the excessive use of mercenaries led to much peasant resentment, giving the Ottomans support in the regions in Asia Minor. The Ottomans subjugated the Byzantines as vassals in the late 14th century and attempts to relieve this vassal status culminated in the Fall of Constantinople in 1453.
- The Fourth Crusade which sacked Byzantium, and reduced Imperial power to the Nicaean Empire, Trebizond and Epirus.
- The rise of Islam, made the Latin Church decline in its power over the empire
- A series of societal infighting also weakened the Byzantine Empire's military power.
- Another possible explanation for the disintegration of the Byzantine Empire is the permanent settlement of Anatolia by the Seljuks, a Turkish people between the 11th – 13th century.
- The arrival of the Seljuk Turks led to the rise of the Ottomans, warriors that followed the Noble (Bey) Osman I. Attempts by the Byzantine Emperors to drive back the Ottomans yielded little short term success – the excessive use of mercenaries led to much peasant resentment, giving the Ottomans support in the regions in Asia Minor. The Ottomans subjugated the Byzantines as vassals in the late 14th century and attempts to relieve this vassal status culminated in the Fall of Constantinople in 1453.