Asia-Europe boundary

The Don River became unsatisfactory to northern Europeans when Peter the Great, king of the Tsardom of Russia, defeating rival claims of Sweden and the Ottoman Empire to the eastern lands, and armed resistance by the tribes of Siberia, synthesized a new Russian Empire extending to the Ural Mountains and beyond, founded in 1721. The major geographical theorist of the empire was actually a former Swedish prisoner-of-war, taken at the Battle of Poltava in 1709 and assigned to Tobolsk, where he associated with Peter's Siberian official, Vasily Tatishchev, and was allowed freedom to conduct geographical and anthropological studies in preparation for a future book.[citation needed]
At home in Sweden again, five years after Peter's death, in 1730 von Strahlenberg published a new atlas proposing the Urals as the border of Asia. The Russians were enthusiastic about the concept, which allowed them to keep their European identity in geography as well as other cultural heritage. Tatishchev announced that he had proposed the idea to von Strahlenberg. The latter had suggested the Emba River as the lower boundary. Over the next century various proposals were made until the Ural River prevailed in the mid-19th-century. The border had been moved perforce from the Black Sea to the Caspian Sea into which the Ural River projects.[8] In the maps of the period, Transcaucasia was counted as Asian. The incorporation of most of that region into the Soviet Union tended to push views of the border to the south.