The Battle of Poltava took place on June 27, 1709, during the Great Northern War. It was a decisive conflict between the forces of the Swedish Empire, led by King Charles XII, and the Russian Empire, commanded by Tsar Peter the Great. The battle marked a turning point in the war, as the Russian army's victory significantly weakened Swedish power in the region. Following the battle, the defeat of the Swedish forces led to the decline of their influence in Eastern Europe. The victory at Poltava established Russia as a major European power and solidified Peter the Great's reforms, which aimed to modernize the Russian military and government.