This article discusses the practice of dedicating churches to saints in cities on the territory of the state of the Teutonic Order in Prussia. Special attention is paid to three church groups — parish churches, churches owned by monastic orders — Dominicans, Franciscans, Cistercians and Augustinians — Heremites, as well as cathedrals in the capitals of the bishoprics of Kulm, Pomesan, Warmia and Sambia. Among the most popular patron saints was the Virgin Mary, which was due to her patronage of the Teutonic Order as well as the cultural influence of the Hanseatic cities, and her veneration in certain mendicant orders such as the Cistercians. Other popular saints included St Peter and St Paul, and St Nicholas, who also acted as the patron saint of merchants. St Adalbert was also worshipped locally, due to his missionary work in Prussia. Patrons of the churches were also venerated in medieval Europe and were introduced to the region during the process of Christianization.