In the past, religion used to play a very important role in the giving of proper names. The object of this study is to show the Orthodox Parish registry books as a valuable source of the socioonomastics studies. The given names of the Orthodox Church members and the converts to the Orthodox Christianity in Cuyavia and Dobrzyń Land can be determined by the Orthodox calender. This paper focuses ofthe baptismal names ofWłocławek, Rypin, Lipno and Aleksandrów Kujawski.Projekt Operacyjny Polska Cyfrowa POPC.02.03.01-00-0039/1
