With Öz Beg's assistance, the Grand duke Mikhail Yaroslavich won the battle against the party in Novgorod in 1316. While Mikhail was asserting his authority, his rival Yury of Moscow ingratiated himself with Öz Beg so that he appointed him chief of the Rus' princes and gave him his sister, Konchak, in marriage. After spending three years at Öz Beg 's court, Yury returned with an army of Mongols and Mordvins. After he ravaged the villages of Tver, Yury was defeated by Mikhail in December 1318, and his new wife and the Mongol general, Kawgady, were captured. While she stayed in Tver, Konchak, who converted to Christianity and adopted the name Agatha, died. Mikhail's rivals suggested to Öz Beg that he had poisoned the Khan's sister and revolted against his rule. Mikhail was summoned to Sarai and executed on November 22, 1318. Yuri became grand duke once more. Yuri's brother Ivan accompanied the Mongol general Akhmyl in suppressing a revolt by Rostov in 1320. In 1322, Mikhail's son, Dmitry, seeking revenge for his father's murder, went to Sarai and persuaded the Khan that Yury had appropriated a large portion of the tribute due to the Horde. Yury was summoned to the Horde for a trial, but he was killed by Dmitry before any formal investigation. Eight months later, Dmitry was also executed by the Horde for his crime. The title of grand duke went to Aleksandr Mikhailovich.