yarlik of office for the grand princely throne in 1322, after he had persuaded the khan that Yury had appropriated a large portion of the tribute due to the Horde. Yury was summoned to the Horde in Sarai for a trial but, before any formal investigation, was killed by Dmitry, November 21, 1325. Öz Beg waited to punish Dmitri and eventually he arrested the Prince of Tver for the murder, executing him in 1326. When the Khan's cousin, the baskak Shevkal, and his Tatars were killed in Tver and a rebellion erupted there in mid-August 1327, Dmitry's successor as Prince of Tver and Grand Prince of Vladimir-Suzdal, his brother Alexander Mikhailovich, fled first to Novgorod—which turned him away—and then to Pskov—which made him its Prince—in order to escape a punitive expedition of 50,000 Mongol-Tatars & Muscovites, which was headed by his cousin, Yury's brother & successor Ivan Daniilovich. Tver's uprising against the Horde was bloodily suppressed by the Muscovite and Tatar forces in 1327. Öz Beg appointed Ivan to position of Grand Duke of Vladimir in 1332; that marked the true beginning of the rise of the Muscovites. Alexander, after many travails, including exile in Sweden & Lithuania, eventually prospered in Pskov, under the patronage of Gediminas, Grand Duke of Lithuania. He sent his son Fyodor to the Horde, with tribute and seeking forgiveness, in 1335; the Khan pardoned Alexander and he was given the princely yarlik to Tver once again in 1337. Unfortunately, his greatest enemy, his cousin Ivan, once more set the Horde's Khan against him with the aid of intrigue. Alexander was summoned to the Horde again and was executed at the hand of Khan Öz Beg; Tver was then pillaged and many of its citizens massacred. Öz Beg welcomed Ivan's sons and made Simeon Grand Prince (duke) in 1340. Simeon was given more powers by the Khan to counter Lithuania's growing power. Öz Beg also launched military expeditions into Lithuania, as it was clear that it threatened Mongol dominance in Russia. Relationship with Ruthenian princes After Öz Beg's army killed Lev II and his brother Andrey (co-kings of Galicia-Volhynia, and last of the Rurikid dynasty) in 1323, the Grand Duchy of Lithuania and the Kingdom of Poland had access to control over Galicia-Volhynia. The Lithuanians defeated the Rus' boyars and occupied Kiev and its surrounding areas. In 1337, the joint Russian and Horde army penetrated to