Some preliminary results of research on orientation of some Paleochristian and Byzantine churches of Dobrogean area (Capidava, Histria, Niculitel), Romania, are reported with conclusion. For some religions, the celebration of the saint who was to patronize the church was found through the direct view on the physical horizon of the sunrise point, which determined the placement of the altar and thus the longitudinal axis of the church. This way of drawing out allows us nowadays to determine the patron of some churches of which there remained only ruins. The paper also describes a computer database as well as a series of drafts regarding the analysed churches - a part of the archaeometrical and archaeoastronomical research developed in Romania within the framework of the "AstroDacia" Project. The universities of Cluj, Iasi, Sibiu and Alba-Iulia as well as the Museum of History in Bucharest, Cluj-Napoca and Deva also joint this project.