The Battle of Abensberg took place on 20 April 1809 between a Franco-German force under the command of Emperor Napoleon I of France and a reinforced Austrian corps led by Feldmarschall-Leutnant Archduke Louis of Austria. As the day wore on, Feldmarschall-Leutnant Johann von Hiller arrived with reinforcements to take command of the three corps that formed the Austrian left wing. The action ended in a complete Franco-German victory. The battlefield was southeast of Abensberg and included clashes at Offenstetten, Biburg-Siegenburg, Rohr in Niederbayern, and Rottenburg an der Laaber. On the same day, the French garrison of Regensburg capitulated.

After Marshal Louis-Nicolas Davout's hard-fought victory at Battle of Teugen-Hausen the previous day, Napoleon determined to break through the Austrian defenses behind the Abens River. The emperor assembled a provisional corps consisting of part of Davout's corps plus cavalry and gave Marshal Jean Lannes command over it. Napoleon directed his German allies from the Kingdom of Bavaria and the Kingdom of Wrttemberg to attack across the Abens from the west, while Lannes thrust from the north toward Rohr. While the Austrians initially held the river line, Lannes' strike force crashed through Louis' defenses farther east. On the left, the Austrians managed to conduct a capable rear guard action, but during the day the French smashed their opponents' right flank and captured thousands of soldiers. The day ended with the Austrians barely holding onto a line behind the Groe Laber River.

The next day, Hiller withdrew to Landshut, separating the left wing from the main army under Generalissimo Archduke Charles, Duke of Teschen near Regensburg (Ratisbon). The French surrender of Regensburg on 20 April allowed Charles' army a retreat route to the north bank of the Danube. The Battle of Landshut was fought on 21 April.

The First French Empire, officially the French Empire, also known as Napoleonic France, was the empire ruled by Napoleon Bonaparte, who established French hegemony over much of continental Europe at the beginning of the 19th century. It lasted from 18 May 1804 to 11 April 1814 and again briefly from 20 March 1815 to 7 July 1815. (French: Empire français; Latin: Imperium Francicum),

Although France had already established a colonial empire overseas since the early 17th century, the French state had remained a kingdom under the Bourbons and a republic after the French Revolution. Historians refer to Napoleon's regime as the First Empire to distinguish it from the restorationist Second Empire (1852–1870) ruled by his nephew Napoleon III.

On 18 May 1804, Napoleon was granted the title Emperor of the French (Empereur des Français, pronounced [ɑ̃.pʁœʁ de fʁɑ̃.sɛ]) by the French Sénat conservateur and was crowned on 2 December 1804, signifying the end of the French Consulate and of the French First Republic. Despite his coronation, the empire continued to be called the "French Republic" until 1809. The French Empire achieved military supremacy in mainland Europe through notable victories in the War of the Third Coalition against Austria, Prussia, Russia, Britain and allied nations, notably at the Battle of Austerlitz in 1805. French dominance was reaffirmed during the War of the Fourth Coalition, at the Battle of Jena–Auerstedt in 1806 and the Battle of Friedland in 1807, before Napoleon's final defeat at the Battle of Waterloo in 1815.

A series of wars, known collectively as the Napoleonic Wars, extended French influence to much of Western Europe and into Poland. At its height in 1812, the French Empire had 130 departments and a population of 44 million people, it ruled over 90 million subjects, maintained an extensive military presence in Germany, Italy, Spain, and Poland, and counted Austria and Prussia as nominal allies. Early French victories exported many ideological features of the Revolution throughout Europe: the introduction of the Napoleonic Code throughout the continent increased legal equality, established jury systems and legalized divorce, and seigneurial dues and seigneurial justice were abolished, as were aristocratic privileges in all places except Poland. France's defeat in 1814 (and then again in 1815), marked the end of the First French Empire and the beginning of the Bourbon Restoration.