The chronological order of the events is:
1. Defeat of Napoleon (1815): Marked the end of the Napoleonic era and reshaped the political landscape of Europe.
2. Treaty of Constantinople (1832): Established Greece as an independent nation.
3. Unification of Italy (1861): A significant step in the unification of Italian states.
4. Unification of Germany (1871): Led by Otto von Bismarck, it established the German Empire.