Complex sentence: Territory east of the Ural Mountains was seen as undesirable; however, the Germans later decided to expand the frontier of their proposed empire to the Urals and send the remaining Slavic populations over the mountains and thus out of Europe.
Split into simpler sentences: Territory east of the Ural Mountains was seen as undesirable. However, the Germans later decided to expand the frontier of their proposed empire to the Urals and send the remaining Slavic populations over the mountains and thus out of Europe.