information:highlighting, linguistic:voice_change
Struggle against Mamai

Mongol domination of Rus' began to crumble during Dmitry's thirty-year reign. The Golden Horde was severely weakened by civil war and dynastic rivalries. Dmitry took advantage of this lapse in Mongol authority to openly challenge the Tatars. While he kept the Khan's patent to collect taxes for all of Russia, Dmitry is also famous for leading the first Russian military victory over the Mongols. Mamai, a Mongol general and claimant to the throne, tried to punish Dmitry for attempting to increase his power. In 1378 Mamai sent a Mongol army, but it was defeated by Dmitry's forces in the Battle of Vozha River.

Two years later Mamai personally led a large force against Moscow. Sergius of Radonezh blessed Dmitry Donskoy when he went to fight the Tatars in the signal Battle of Kulikovo field, but only after he was certain Dmitry had pursued all peaceful means of resolving the conflict. Sergius sent the two warrior monks Alexander Peresvet and his friend Rodion Oslyabya to join the Russian troops. The battle of Kulikovo was opened by single combat between two champions. The Russian champion was Alexander Peresvet. The Horde champion was Temir-murza. The champions killed each other in the first run. Dmitry defeated the Horde. In gratitude for the victory, Dmitry established the Dormition monastery on the Dubenka River and built a church in honor of the Nativity of the Holy Theotokos over the graves of the fallen warriors.

The defeated Mamai was presently dethroned by a rival Mongol general, Tokhtamysh. That khan reasserted Mongol rule of Rus and overran Moscow in 1382 for Dmitry's resistance to Mamai. Dmitry, however, pledged his loyalty to Tokhtamysh and to the Golden Horde and was reinstated as Mongol principal tax collector and Grand Duke of Vladimir. Upon his death in Moscow in 1389, Dmitry was the first Grand Duke to bequeath his titles to his son Vasily I of Moscow without consulting the Khan.