sentences:  At the time, the Bolsheviks had just gained control of the majority of Russian territory, and their government's legitimacy was being hotly contested by Western powers and the Russian White movement.In 1030 Yaroslav the Wise of Kievan Rus organised a military expedition to the territory of Chuds and built a fort he called Yuryev on the site of their former stronghold (in modern Tartu).In 1060, Kievan Rus taxed Sosols (Estonian tribe), next year Sosols rose up, attacked Yuryev and destroyed it.