How has the rise of celebrities who are "famous for being famous" influenced the world's perception of American culture?

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).

an era of negotiation.

is that an answer to your question?

the soviet union wanted to impose communist governments in eastern europe.