The main reasons for the weakening of Byzantium in the 10th -13th centuries.

The main reasons for the weakening of Byzantium include:

1) Internal political instability;

2) Constant internal uprisings that took place, then in one province, then in another.

3) The emergence of the Seljuk Turks.

Thus, the decline of a powerful state took place, which for a long period of time occupied dominant positions in Asia and Europe. The final fall of Byzantium took place in the 15th century, when all of its lands were captured by the Seljuk Turks.