There were many factors that allowed the Byzantine Empire to last a 1000 years after the end of the Roman Empire which include the fact that Constantinople, the capital of the Byzantine Empire, was protected with walls that lasted almost the entire 1000 years, making Constantinople, and the center of the empire's economy/culture impervious to invaders.
Well they invented the abacus and the wheel
(A) the regimes coordinated efforts to seek and provide weapons for use in attacking the United States and its allies
Nationalism spread across Europe during Napoleon's time. It was repressed for a generation under the Congress of Vienna and the Concert of Europe until the revolutions of 1845/1845. The term "Nationalism" can be defined as a group of people with the same nationality should unite together under a single flag. Napoleon nationalised France and then moved across the rest of Europe, conquering countries along the way. Eventually, Napolean was defeated and the Congress of Vienna was held by the heads of the European countries. The aim of these meeting was to ensure peace and stability in Europe. The revolutions of 1845/1848 overthrew the repressive European governments of the day.
