In opulent and multithread literary output o f excellent Polish historian Gerard Labuda (1919-2010), first of all medieval researcher, whose bibliography contains 2 thousand publications, on one of the leading place is the history o f the Church. Let’s note, that these inquiries refer to political and organizational matters and the beginning o f State system. As the student he wrote the dissertations concerning Polish and Teutonic Order mission in Prussia and the attempts of Gniezno subordination made by German Magdeburg, published before 1939. Published in 1946 the work qualifying for assistant-professor-ship concerning the beginning of the Piast state (1946) contains in great part the matters connected with the reception o f the Catholicism, enriched in two volumes edition (1987-88) and enlarged in series of the dissertations, collected in Historical essays X and XI century. The history of the Church organization in Poland in early Middle Ages (2004). The special position in G. Labuda output have two fundamental monographs concerned with Saint Wojciech - the Bishop o f Prague (2000) and Saint Stanisław - the Bishop of Kraków (2000). That last waited for its publication long time, because the author stopped it several years ago to not be used by communist Poland propaganda to the fight against the Church. In both two books scientific mastery connected with medieval specialization o f the author was shown. Besides the monographs and the dissertations, the author explored the history of the Church in many critical reviews written as extended articles. He was devoted to the studies concerning Teutonic Order in Prussia and edited in many volumes synthesis, especially History of Pomerania and History of Polish diplomacy, and also published historical sources, sometimes chronologically not connected with the Middle Ages The Chronicle of the Franciscans cloister in Wejherowo in 1633-1676 written by Grzegorz o f Gdańsk ( 1996) and the reedition of Saint Wojciech Life (1998). Professor Gerard Labuda participated in many editorial works and the conferences organized by the Church institutions, Karol Wojtyła as the Bishop of Kraków and the Cardinal and also as the Pope John Paul II read his books with interest.