What is the article of alliance

Alliance, in international relations, a formal agreement between two or more states for mutual support in case of war.

Explanation:

Alliance is defined as a written agreement between two or more parties in order to forge a bond, and/or work together to serve both sides interests. An example of an alliance is a treaty signed by countries once a war is over, and serves as an agreement to work together in the future.

the conditions that made the byzantine empire vulnerable to attacks by the muslin turks were the sack of constantinople by western crusaders, the conquests of the sultanate of rum, presence of rival kingdoms and finally the set up of fiefdoms at the empire which were owned by the ghazis (turkish warriors).