Despite the fall of rome, the byzantine empire continued to stay strong because justinian

although the crusades failed to capture jerusalem, they had several major impacts on western europe. they increased the authority of the king: sometimes nobles died in battle without leaving an heir in which case the king got their land. kings passed taxes to pay for the crusades.

the safahids used force when persuasion to convert from being a sunni muslim to embrace shi'ism was not effective. they also persecute shi'ites who have different views from their imposed teachings.