Charles guiteau most likely assassinated president garfield because

Charles Guiteau believed he had been pivotal to the victory of President Garfield, and thus deserved a position. He wanted a consulship in Vienna or Paris, but after several attempts, he was denied the position. Guiteau was extremely offended, and shot Garfield at the Baltimore and Potomac Railroad Station on July 2, 1881. Although the president did not immediately died, he died two months later from infections related to this wound. Guiteau was sentenced and hanged for the crime.

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).