found themselves fighting each other especially after their defeat to the Cuman forces in 1068 at the Battle of the Alta River. At the same time, an uprising took place in Kiev, bringing to power Vseslav of Polotsk who supported the traditional Slavic paganism. The ruling Grand Prince Iziaslav fled to Poland asking for support and in a couple of years returned to establish the order. The affairs became even more complicated by the end of the 11th century driving the state into chaos and constant warfare. On the initiative of Vladimir II Monomakh in 1097 the first federal council of Kievan Rus' took place near Chernigov in the city of Liubech with the main intention to find an understanding among the fighting sides. However, even though that did not really stop the fighting, it certainly cooled things off. By 1130, all descendants of Vseslav the Seer had been exiled to the Byzantine Empire by Mstislav the Great. The most fierce resistance to the Monomakhs was posed by the Olegovichi when the izgoi Vsevolod II managed to become the Grand Prince of Kiev. The Rostislavichi who had initially established in Halych lands by 1189 were defeated by the Monomakh-Piast descendant Roman the Great. The decline of Constantinople—a main trading partner of Kievan Rus'—played a significant role in the decline of the Kievan Rus'. The trade route from the Varangians to the Greeks, along which the goods were moving from the Black Sea (mainly Byzantine) through eastern Europe to the Baltic, was a cornerstone of Kievan wealth and prosperity. These trading routes became less important as the Byzantine Empire declined in power and Western Europe created new trade routes to Asia and the Near East. As people relied less on passing through Kievan Rus' territories for trade, the Kievan Rus' economy suffered. The last ruler to maintain a united state was Mstislav the Great. After his death in 1132, the Kievan Rus' fell into recession and a rapid decline, and Mstislav's successor Yaropolk II of Kiev, instead of focusing on the external threat of the Cumans, was embroiled in conflicts with the growing power of the Novgorod Republic. In March 1169, a coalition of native princes led by Andrei Bogolyubsky of Vladimir sacked Kiev. This changed the perception of Kiev and was evidence of the fragmentation of the Kievan Rus'. By the end of the 12th century, the Kievan state fragmented