Final answer:
The Battle of Trafalgar was a decisive naval engagement during the Napoleonic Wars where the British defeated the combined French and Spanish fleets, affirming British naval dominance and influencing Napoleon to focus on terrestrial conquests in Europe.
Step-by-step explanation:
The Battle of Trafalgar in 1805 played a significant role in the Napoleonic Wars. It occurred when Napoleon Bonaparte was exerting his military dominance across Europe. While Napoleon's ground forces achieved success at the Battle of Ulm in October 1805, his navy, bolstered by Spanish forces, suffered a major defeat at Trafalgar against the British navy, led by Vice Admiral Horatio Nelson on October 21, 1805. The outcome was pivotal, as it showcased the inability of Napoleon to challenge British naval supremacy. Consequently, Napoleon shifted his focus to continental dominance using his formidable army.
As Great Britain was heavily invested in the Napoleonic Wars, it could not devote its full military resources to the burgeoning conflict with the United States, which would later become the War of 1812. Despite the setback at Trafalgar, Napoleon managed to secure significant victories over Austria and Russia in the following years, expanding his control over much of Europe.
However, Trafalgar confirmed British naval dominance that would last for a century and influenced the global balance of power, affecting other nations' interactions with Great Britain and their own colonial and military pursuits.