On 31 July 1901, Leonid Feodorov entered into the Catholic Church at the Jesuit Church of the Gesù in Rome.
Leonid was born into the Orthodox Church in Russia and had even contemplated becoming an Orthodox priest, but after becoming acquainted with Western literature grew interested in Roman Catholicism.
After his conversion, he entered into a seminary of the Society of Jesus under a pseudonym to keep himself hidden from the Russian Secret Police. In the seminary he would decide not to become a Latin Rite priest, instead choosing to remain in the Eastern Rite so as to better serve the Russian people. He was ordained on 25 March 1911.
After returning to Russia, he was immediately exiled to Siberia by the Russian government, but was freed after the February 1917 revolution and appointed Exarch of the Russian Catholic Church and secretly consecrated as bishop.
After the Bolshevik Revolution, Fedorov would be tried in 1923 for counter-revolutionary activities and was sentenced to three years at the infamous Butyrka prison in Moscow and then to exile at the Solovki prison camp.
While at Solovki, Fedorov would offer the Divine Liturgy in secret.
He was released on 6 August 1929 and would die on 7 March 1935.
He was beatified by Pope John Paul II on 27 June 2001.