Which battle in 1807 gave Napoleon victory over the Russian army?

The Battle of Friedland gave Napoleon victory over the Russian army in 1807. Fought on 14 June near Friedland in East Prussia, the battle was a decisive French triumph during the War of the Fourth Coalition.

Russian commander Levin August von Bennigsen initially attacked Marshal Jean Lannes's advance force near the town. Lannes held the Russians in place long enough for Napoleon to bring the main French army onto the battlefield. By the afternoon, Napoleon had concentrated roughly 80,000 French troops against a Russian army of about 50,000–60,000.

The Russians had crossed the Alle River and were positioned with the river behind them. Napoleon exploited that vulnerability with a major assault against the Russian left. French pressure eventually broke the Russian line, forcing troops into a chaotic retreat across the river. Russian losses were far heavier than French losses, though exact totals vary among sources.

Friedland helped persuade Tsar Alexander I to negotiate. The resulting Treaties of Tilsit, signed in July 1807, temporarily made peace between France and Russia and marked the high point of Napoleon's influence in Europe. It is often confused with Eylau, fought earlier that year; Eylau was inconclusive, while Friedland was a clear French victory.