Metropolitan Alexius of Moscow, born in Moscow at the turn of the 13th and 14th centuries into a noble boyar family, was baptized with the name Simeon. His godfather was the young prince Ioann, the future Grand Prince of Moscow Ivan Kalita. Both played a significant role in the rise of Moscow as the center of the unification of Rus, which was under foreign oppression.

In a dream, the future metropolitan heard a voice reproaching him for wasting time catching birds, pointing to his true calling, "to catch people." Since then, Eleutherius often visited the church.

At the age of 19, Alexius took monastic vows from the abbot Stefan, the elder brother of Sergius of Radonezh, at the Epiphany Monastery, which was then located outside the city and is now situated in the center of Moscow, in Kitai-gorod.

Possessing outstanding abilities, by the age of forty, Alexius became the official successor to the elderly Metropolitan of Kiev Theognost. The title "Kiev" by that time was nominal, as metropolitans had been living in Moscow since 1325.

In 1354, Alexius traveled to Constantinople, where Russian primates were confirmed in their positions. The Ecumenical Patriarch made an exception and confirmed him as metropolitan, although usually Russian primates were chosen from the Greeks. Patriarch Philaret elevated Alexius to the rank of Metropolitan of Kiev and all Rus.

On the return journey from his second trip to Constantinople, undertaken to resolve a dispute with the Lithuanian metropolitanate, Alexius encountered a storm and vowed to establish a monastery in Moscow if he was saved. Thus, the Spaso-Andronikov Monastery was founded.

Upon his return, Metropolitan Alexius took active measures, appointing new bishops and combating church discord, setting an example of Christian life. It was during his time that the residence of the metropolitans was moved from Kiev to the northeast.

By 1357, rumors of his virtues reached the Horde, and the khan's wife Taidula, suffering from an eye disease, invited him for healing. Through Alexius's prayers, she recovered and freed the Church from tributes. In gratitude, the saint was gifted land in the Kremlin, where he founded the Chudov Monastery.

In Moscow, Alexius wielded immense influence and was effectively a co-ruler. At his initiative, the construction of the white-stone Kremlin began. He also blessed the founding of the Chudov and Simonov Monasteries in Moscow and the Vvedensky Monastery in Serpukhov, supporting the establishment of communal monasteries.

After the death of Ivan II the Red, Alexius took under his wing his son Dmitry (the future Don Prince), effectively governing Rus and trying to unite the princes.

At that time, there was a change of ruler in the Horde: Janibek was killed by his son, who demanded an increase in tribute. Alexius went to the Horde again, and Taidula persuaded her son to soften the demands.

The metropolitan actively participated in the unification of Russian lands to fight against the yoke, being the initiator of the alliance between Moscow and Great Novgorod. During his time, agreements between princes began to be sealed with the metropolitan seal.

As a residence, Alexius chose Cherkizovo with a wooden Ilyinsky church, near which was the village of Izmaylovo, although its existence at that time is not confirmed.

The saint passed away in 1378 and was buried at the altar of the Chudov Monastery in the presence of Grand Prince Dmitry Ivanovich and his sons. Half a century later, he was canonized, and his relics remained in the monastery until the 20th century.

After the monastery was closed, the relics were saved and in 1947 transferred to the Epiphany Cathedral in Yelokhovo, which was the cathedral of Moscow until the restoration of the Cathedral of Christ the Savior.