The major political changes in 19th century Europe were
1. The Napoleonic wars from 1803-1814, which led to the annexation of large parts of Europe by France.
2. The spread of the ideals of the French Revolution to the parts of Europe that were conquered by Napoleon.
3. Reestablishment of conservative governments in Europe after the defeat of Napoleon.
4. Widespread revolutions in 1848 against the conservative governments of Europe.
75. Unification of Germany and Italy in 1871.