the Saint Petersburg Roman Catholic Theological Academy. He earned the Candidate of Philosophy degree for the thesis on the Pope Honorius I and Third Council of Constantinople in 1898 and Master's of Theology for the thesis on Saint Stanislaus of Szczepanów in 1899. He was ordained as a priest on 25 March 1899. At the academy, Būčys studied with Jurgis Matulaitis-Matulevičius starting their life-long friendship. He was also close with Lithuanian professors at the academy: he inherited property of Kazimieras Jaunius and wrote a 2,426-page biography of Justinas Pranaitis though it remains unpublished. He continued to contribute to Lithuanian press, including to Tėvynės sargas and Žinyčia. Together with Matulaitis-Matulevičius, he further studied apologetics under professor at the University of Fribourg in Switzerland using an assumed name because the Tsarist police allowed Būčys to depart the Russian Empire for medical treatments, not for studies. In Fribourg, he joined the Lithuanian student society Rūta (rue). He was with Matulaitis-Matulevičius when he was operated for bone tuberculosis. To earn a living, Bučys held masses in Autigny and was chaplain of a girls' agricultural school in . He defended his expanded thesis on Saint Stanislaus, which was translated from Latin to Polish and published in 1902, and earned Doctor of Theology in July 1901. Saint Petersburg and United States Upon return to Lithuania in late 1901, Būčys hoped to become an editor of a Lithuanian newspaper and live in Tilsit (present-day Sovetsk, Kaliningrad Oblast). But bishop Antanas Baranauskas assigned him as a priest in his native Slavikai and as professor at the Sejny Priest Seminary before moving to the Saint Petersburg Roman Catholic Theological Academy in August 1902. He taught apologetics and fundamental theology not only to the clerics at the academy but also to students at other universities. His students included Mečislovas Reinys, Mykolas Krupavičius, Juozas Purickis, Vladas Jurgutis. In his memoirs, Bučys highlighted two weaknesses of his teaching methods – he emphasized ability to think rather than knowledge of facts and spent too much time analyzing anti-religious arguments. In 1912, Būčys became prorector of the Theological Academy. When rector Aleksander Kakowski became Archbishop of Warsaw, Būčys was an acting rector from May 1913 to March 1915, but as a non-Pole was not officially confirmed as rector. Upon learning that he would not become rector, he resigned from the academy and briefly worked as a religion teacher at different schools and as a