1810s

The 1810s (pronounced "eighteen-tens") was a decade of the Gregorian calendar that began on January 1, 1810, and ended on December 31, 1819.

The decade was opened with a very hostile political climate around the world. Napoleon was invading France's neighbours in efforts to build a French Empire, causing a chain of global-scaled conflicts known as the Napoleonic Wars. Here, France's Napoleonic empire saw its rise and fall through events such as Napoleon's attempts to conquer Russia, the War of 1812 (spillover to America), and the Battle of Waterloo (Napoleon's ultimate defeat). Imperialism began to encroach towards African and Asian territories through trade, as the United States saw mass-scaled migration that headed westward towards the American frontier (mostly through the opening of the Oregon Trail.)

In 1810, the French Empire reached its greatest extent. On the continent, the British and Portuguese remained restricted to the area around Lisbon and to besieged Cádiz. Napoleon married Marie-Louise, an Austrian Archduchess, with the aim of ensuring a more stable alliance with Austria and of providing the Emperor with an heir. As well as the French Empire, Napoleon controlled the Swiss Confederation, the Confederation of the Rhine, the Duchy of Warsaw and the Kingdom of Italy. Territories allied with the French included: the Kingdom of Spain, the Kingdom of Westphalia, the Kingdom of Naples, the Principality of Lucca and Piombino, and Napoleon's former enemies, Prussia and Austria. Denmark–Norway also allied with France in opposition to Great Britain and Sweden in the Gunboat War.

The French invasion of Russia of 1812 was a turning point, which reduced the French and allied invasion forces (the Grande Armée) to a tiny fraction of their initial strength and triggered a major shift in European politics, as it dramatically weakened the previously dominant French position on the continent. After the disastrous invasion of Russia, a coalition of Austria, Prussia, Russia, Sweden, the United Kingdom, and a number of German States, and the rebels in Spain and Portugal united to battle France in the War of the Sixth Coalition. Two-and-a-half million troops fought in the conflict and the total dead amounted to as many as two million. This era included the battles of Smolensk, Borodino, Lützen, Bautzen, and the Dresden. It also included the epic Battle of Leipzig in October, 1813 (also known as the Battle of Nations), which was the largest battle of the Napoleonic wars, which drove Napoleon out of Germany.

The final stage of the War of the Sixth Coalition, the defense of France in 1814, saw the French Emperor temporarily repulse the vastly superior armies in the Six Days Campaign. Ultimately, the Allies occupied Paris, forcing Napoleon to abdicate and restoring the Bourbons. Napoleon was exiled to Elba. Also in 1814, Denmark–Norway was defeated by Great Britain and Sweden and had to cede the territory of mainland Norway to the King of Sweden at the Treaty of Kiel.

Napoleon shortly returned from exile, landing in France on March 1, 1815, marking the War of the Seventh Coalition, heading toward Paris while the Congress of Vienna was sitting. On March 13, seven days before Napoleon reached Paris, the powers at the Congress of Vienna declared him an outlaw; four days later the United Kingdom, Russia, Austria and Prussia, members of the Seventh Coalition, bound themselves to put 150,000 men each into the field to end his rule. This set the stage for the last conflict in the Napoleonic Wars, the defeat of Napoleon at the Battle of Waterloo, the restoration of the French monarchy for the second time and the permanent exile of Napoleon to the distant island of Saint Helena, where he died in May 1821.

Spain in the 1810s was a country in turmoil. Occupied by Napoleon from 1808 to 1814, a massively destructive "war of independence" ensued, driven by an emergent Spanish nationalism. Already in 1810, the Caracas and Buenos Aires juntas declared their independence from the Bonapartist government in Spain and sent ambassadors to the United Kingdom. Colombia, once become part of New Granada became the first Spanish colony in South America to declare independence from Spain on 20 July 1810 as the third oldest independent republic in the New World after Haiti and the United States. The British blockade against Spain had also moved most of the Latin American colonies out of the Spanish economic sphere and into the British sphere, with whom extensive trade relations were developed. The remaining Spanish colonies had operated with virtual independence from Madrid after their pronouncement against Joseph Bonaparte.

The Spanish government in exile (Cortes of Cádiz) created the first modern Spanish constitution. Even so, agreements made at the Congress of Vienna (where Spain was represented by Pedro Gómez Labrador, Marquis of Labrador) would cement international support for the old, absolutist regime in Spain.