Charlemagne became the ruler of europe by the sword and the cross. bribing neighboring tribes with money. killing all other heirs to his throne. 3 points saved question 4 at the height of charlemagne's reign, the frankish kingdom spanned all of the following modern-day countries except france. the czech republic. switzerland. 3 points saved question 5 charlemagne restored order in the old roman empire by establishing a central government over western europe. practicing christianity. maintaining a strong military force.