The Battle of Poltava on June 27, 1709 (8 July, N.S.)

is the decisive victory of Peter I of Russia over the Swedish forces under Field Marshal Carl Gustav Rehnskiöld in one of the battles of the Great Northern War.

It is widely believed to have been the beginning of Sweden's decline as a Great Power; the Russians (Russian Empire from 1721) take their place as the leading nation of northern Europe.