The Venerable Grand Duke Dimitri Donskoy, son of Prince John the Red and Princess Alexandra, grandson of John Kalita, was born on October 12, 1350, and was raised in love for God and the Holy Church under the guidance of St. Alexy of Moscow. St. Sergius of Radonezh greatly assisted the saint in the education of the prince. From an early age, Dimitri, listening to his father's stories about his glorious ancestors — Alexander Nevsky, Daniel of Moscow and other pious princes, strengthened his responsibility for his origins. As a nine-year-old boy, after his father's death, Dimitri went to the Horde and received permission from the khan to inherit his father's reign.
The Christian piety of Saint Prince Dimitri was combined with the talent of an outstanding statesman. Dimitri fortified Moscow, surrounding the Kremlin with walls of white stone instead of oak ones that burned down during the fire, and put cannons on the walls — the latest weapons of the time. Moscow was able to withstand three sieges by a huge Lithuanian army. Dimitri devoted himself to the cause of uniting the Russian lands under the leadership of the Grand Dukes of Moscow and the liberation of Russia from the Tatar-Mongol yoke. For all his deeds, the Grand Duke received the blessing of the Church. Gathering his forces for a decisive battle with Mamai's hordes, Saint Demetrius visited the monastery of the Life-Giving Trinity and told St. Sergius about his doubts due to the small number of his troops (compared to Mamai's army). The monk offered prayers to God and blessed the prince, predicting victory for his Christian army. The elder encouraged the prince and his warriors by sending two Trinity schemers, Alexander (Peresvet) and Andrey (Oslyabya), to help them. Before the battle, Saint Demetrius prayed fervently to God and addressed the soldiers, saying: "Brothers, it is time for us to drink our cup, and may this place become our grave for the name of Christ!" The battle took place on Kulikovo Field, between the Don and Nepryadva rivers, on the feast day of the Nativity of the Blessed Virgin Mary on September 8, 1380.
Before the Russians marched against the Tatars, the relics of St. Alexander Nevsky were discovered in Vladimir. Dimitri Ioannovich found out about this even before the battle and was strengthened by the invisible help from his great ancestor. The battle began with a duel between the monk Alexander Peresvet, who accepted the challenge of the Tatar hero Chelubey. The warriors stumbled and fell dead. The Grand Duke participated in the battle on a par with ordinary warriors. The prediction of St. Sergius came true: the Lord did not abandon the Russian army. Many saw Angels over Kulikovo Field, Archangel Michael, the Passion-bearers Boris and Gleb, and the princely patron saint Demetrius of Thessalonica. The entry into battle of the ambush Russian regiment under the command of Voivode Dimitri Bobrok and Prince Vladimir Andreevich the Brave decided the outcome of the battle. The Tatars fled, abandoning their wagons. For this victory, Grand Duke Dimitri became known as Donskoy.
In gratitude to God and the Blessed Virgin Mary, Saint Demetrius built the Assumption Monastery on the Dubenka River and created a church of the Nativity of the Blessed Virgin on the graves of fallen soldiers. At the same time, in the Trinity Monastery, the holy Prince began the national commemoration of the slain soldiers (this is how the St. Demetrius Parental Sabbath originated).
Before his death, the Grand Duke made a spiritual testament, commanding his children to honor their mother, Grand Duchess Evdokia (Euphrosyne in monasticism; July 7, 1407; canonized), and the boyars to live according to the commandments of God, affirming peace and love. Saint Demetrius reposed to the Lord on May 19, 1389 and was buried in the Archangel Cathedral of the Moscow Kremlin. The canonization of Prince Dimitri took place in 1988.
The memory of the Venerable Grand Duke Dimitry Donskoy is celebrated on May 19 in the old style and on June 1 in the new.