Alexius (Алексей in Russian; in life - Елевферий (Yelevferiy)) (before 1296 — 1378), Metropolitan of Kiev and all Russia (since 1354), writer; came from the family of Feodor Byakont, a boyar from Chernigov.

Alexius took monastic vows in Bogoyavlensky Monastery around 1313. In 1333 or so, he moved to Moscow at the request of the Grand Prince and Metropolitan Theognostus. In 1340, Alexius was appointed Metropolitan's deputy in Vladimir and 12 years later would become the Bishop of Vladimir. By the will of Semeon of Russia, Alexius was appointed adviser to Semeon's brothers - Ivan and Andrei. After visiting Constantinople, he was chosen to become the Metropolitan of Kiev and all Russia in 1354. When Dmitry Donskoy was young, Alexius was his spiritual tutor and a regent at the same time. He took the side of Dmitry Donskoy in his struggle against Tver (1366-1370).

In 1365, Alexius founded the Cathedral of the Archangel Michael in Moscow, Andronikov, Chudov, and Alekseyevsky monasteries. He promoted Metropolitan Peter's canonization by the Russian Orthodox Church. Alexius fruitlessly tried to convince Sergii Radonezhsky to become his successor.

Alexius was also an author sermons and epistles. He was canonized by the Russian Orthodox Church.