Which factor played the largest role in the decline of the byzatine empire

Civil wars. Probably the most important single cause of Byzantium's collapse was its recurrent debilitating civil wars. Three of the worst periods of civil war and internal infighting took place during Byzantium's decline.

Explanation:

they bring people together to achieve control of the government

basically choosinng what sets in   congress and presdicny this is to keepthe antion hole and so it can last because wiht out authority it wouldnt last a week

the answer to your question is

the treaty of hopewell