Andrei of Radonezh, formerly known as Rodion Oslyabya, was a boyar from Lyubutsk and an experienced warrior. He took monastic vows, receiving the name Andrei.

On August 18, 1380, Prince Dmitry of Moscow asked Sergius of Radonezh for a blessing for the Battle of Kulikovo and also requested two warrior-monks, brothers Alexander Peresvet and Andrei Oslyabya, for support. The calling of warrior-monks had primarily spiritual significance. Sergius of Radonezh gave them instead of ordinary weapons the cross of Christ, sewn onto their schematas, and ordered them to replace golden helmets with monastic ones. Handing over the warriors to the prince, Sergius said: "Peace be with you, my brothers, fight bravely against the Tatars, as good warriors, for the faith of Christ and for all Orthodox Christianity."

Andrei participated in the historic battle on the day of the Nativity of the Most Holy Theotokos. It is possible that he fell in battle.

However, there is a version that he survived and served the metropolitans of All Rus. In documents from 1390 and 1393, "monk Andrei Oslyabya" is mentioned among the boyars of Metropolitan Cyprian, and in 1398, "monk Rodion Oslyabya" was an envoy of the Grand Prince in Tsargrad. His son Akinf is mentioned among the boyars of Metropolitan Photius of Kiev in 1425. These mentions may refer to him or his relatives, who traditionally served the metropolitans.

The body of Andrei Oslyabya was buried near the church in honor of the Nativity of the Theotokos "at the old Simonov," next to the body of Alexander Peresvet.

The feat of Peresvet quickly became known in the narratives about the Battle of Kulikovo, but the oldest accounts are silent about Oslyabya. His name did not enter most chronicle lists of those killed on the Kulikovo field and is not mentioned in the synodics of the fallen. Only "Zadonshchina," depicting the monk-warriors as legendary heroes, speaks of the death in battle not only of Alexander Peresvet but also of Andrei Oslyabya, as well as his son Yakov. The death in battle of Peresvet and Oslyabya is also mentioned in the "Tale of the Mamayev Battle."

The time of the local canonization of Alexander and Andrei is unknown. In the 17th century, their names were included in the saints' calendars. In the Menologion of Simon Azaryin from the mid-1650s, it is stated: "The venerable elders Alexander and Rodion, called Peresvet and Oslyabya, were killed at the Mamayev Battle." By the end of the same century, their names as venerable martyrs of Moscow were included in the "Description of Russian Saints." In 1896, their names were also placed in the "Trinity Patericon" (among the "disciples and companions of St. Sergius, not indicated in the menologions").

Over time, tombstones were erected over the remains of Alexander and Andrei, which ended up in "the stone tent under the bell tower." After the dismantling of the bell tower, the tombstones were destroyed, rebuilt in 1794, and arranged with an altar in the 19th century.

In 1928, the Nativity of the Theotokos Church was closed and found itself on the territory of the Dynamo factory. The tombstones were again destroyed and restored only after the revival of the church in 1989 at the initiative of artist P.D. Korin. Now, a canopy has been arranged over the two tombstones in the church, but the remains themselves were not found during restoration work, as this place had been concreted over.

In 1981, the names of the holy monk-warriors were included in the Assembly of Radonezh Saints. It was decided to commemorate them on the eve of the Nativity of the Theotokos feast, on September 7.