Studied at Anagni and Rome, and the Freiburg, Germany. Assisted at the coronation of Pope Pope Pius X on 9 August 1903. Doctorate in philosophy in 1905; degree in theology in 1907. Deacon on 22 March 1911, and ordained a Greek Catholic priest on 25 March 1911 in Bosnia. Monk at the Studite monastery in Bosnia, beginning his noviate on 20 May 1912 and admitted to the habit on 12 February 1913, taking the name Father Leontios.
He returned to Saint Petersburg and was immediately arrested for his faith, and sent to Siberia. Released in March 1917 during an amnesty for political and religious prisoners, he returned to Saint Petersburg, and was appointed Exarch of the Russian Greek Catholic Church. The Communist takeover later that year began a period of persecution of the faith and the faithful, with 1922 ushering in the era of violent suppression of Christianity. All churches were ordered closed on 5 December 1922. Father Leontios and fourteen priests were arrested for their faith in January 1923, sent to Moscow for trial; sentenced to ten years exile to Solovky and Vladka.
Released in 1926, he relocated to Kaluga. Arrested again for spreading the faith, he was sentenced to ten years in Solovetsky where a large monastery had been converted to a prison. There he continued to minister to the faithful, conducting covert Masses, using wine made from raisins sent by the families of prisoners. Transferred to forced labour camp at Pinega on 6 August 1929 where he was billeted with an imprisoned Orthodox priest; after work, Leontios conducted catechism class for local boys. Transferred to Arkhangelsk, to Kotlas, and to Poltava. The poor conditions and steady overwork broke his health, and in 1932 he was certified as an invalid. He completed his sentence in 1933, but was barred from returing to many Russian cities, and had to live in exile the rest of his life. One of the Martyrs Under Communism in Eastern Europe.
Beatified June 27, 2001 by Pope John Paul II in Ukraine
