The Russo–Circassian War, also known as the Russian invasion of Circassia, or termed by the Circassians as the Great War with the Tsar took place in the North Caucasus between July 1763 and June 1864. It began when the Russian Empire entered Circassia and occupied Mozdok, which prompted the Circassian people to organize a resistance movement to preserve their independence. Over the next century, the Imperial Russian Army expanded across the country until the last Circassian fighters were defeated in the Battle of Qbaada. It remains the longest war to have ever occurred in the Caucasus and in the history of Russia, as well as the longest and final war in the history of Circassia. Although it initially involved only Russia and Circassia, the conflict soon drew in a number of other Caucasian nations after they also became targets for Russian conquests, and it is consequently sometimes considered to be the western half of the Caucasian War.