I dont know exactly but the new deal lead to Japan getting mad and attacking Hawaii which was the spark that lead to ww2
The eastern and western deserts prevented invaders from the east and west. The deserts were a hard climate to travel through. Therefore, nobody could walk across to conquer Egypt. Furthermore, the cataracts in the Nile to the south protected the Egyptians from lands below them. So the answer would be that The Nile protected the Egyptians from invasion.
Henry Rathbone was stabbed in the shoulder when Booth shot Lincoln. He had rushed at him immediately after the shot was fired.