In 1917, the Russian Revolution overthrew the tsar and contributed to Russia’s exit from the war.
Wars, famine, natural disasters, etc..
Answer:
In Europe, the Crusades led to economic expansion; increased trade and use of money, which undermined serfdom and led to prosperity of northern Italian cities. They led to increased power of the monarchs, and, briefly, to increased power of the papacy.
Czechoslovakia was a nation for 74 years. From 1918–1992.