Battle of Gross-Jägersdorf

The Battle of Gross-Jägersdorf was a victory for the Russian force under Field Marshal Stepan Fyodorovich Apraksin over a smaller Prussian force commanded by Field Marshal Hans von Lehwaldt, during the Seven Years' War. This was the first battle in which Russia engaged during the Seven Years' War.

Despite the tactical success, supply problems made a successful advance further into East Prussia impractical. Apraksin decided not to take Königsberg and ordered a withdrawal soon after the battle. Suspecting collusion between Apraksin and Chancellor Alexey Bestuzhev-Ryumin, who had opposed the invasion, Elizabeth of Russia removed Apraksin from command, ordered Bestuzhev-Ryumin to face trial for treason, and appointed William Fermor as the head of the army. Femor led the army back into East Prussia in the following year.

Source: Wikipedia