Bishop Leontii was born Lev Bartoshevich in St. Petersburg in 1914. His father fought in the White Army and then moved to Serbia, where his wife could only join him in 1924, coming with their two sons from Soviet Russia. Later, the father moved to Switzerland, while the mother and sons remained in Yugoslavia.
In 1932, Lev graduated from the Russian high school in Belgrade, and in 1938 from the Theological Faculty of the University of Belgrade. He was a spiritual child of St. John of Shanghai and San Francisco and benefited from attending Milkovo Monastery. This was the Russian monastery in Serbia; its abbot, Schema-Archimandrite Ambrose (Kurganov, d. 1933), tonsured a number of future hierarchs of the ROCOR. The future great Serbian spiritual father Fr. Thaddeus (Strabulovich) of Vitovnica began his path there, too. In 1941, both Lev and his older brother Andrei were tonsured monks in the Serbian monastery of Tuman. The same year, Fr. Leontii was ordained by Metropolitan Anastasii to serve in the Russian Church in Belgrade. In 1943, he was assigned to the Russian Church in Geneva, which in 1945–1946 became the center of the ROCOR. After World War II , all bishops save one from the Belarussian Churchб along with several of their counterparts from the Ukrainian Church joined the ROCOR. To counterbalance the number of “outsiders” within its episcopate, the ROCOR consecrated several of “their own,” including Archimandrite Leontii asBishop of Geneva (1950) Vicar of the Western European Diocese of the ROCOR. There were a lot of expectations connected the need to represent the ROCOR at this capital of the ecumenical movement and Leontii’s ability to do so. However, in 1956, Bishop Leontii passed away on the day of the fest of Transfiguration from a complicated case of influenza.
History of the Russian Orthodox Church Outside Russia from Its Beginning to the Present. Part VI. Comprehensive Index of the Bishops of the Church Abroad with Short Biographies
Синодик РПЦЗ. Леотний Бартошевич [A Commemoration book of ROCOR. Leontii Bartoshevich] Archive.
Tikhon I. Troyanov, “People Often Do Not Talk About What’s Important, but Rather about Their Grievances and Frustrations”