In the context of XVI–XVII centuries written sources, this article provides an overview and evaluation of authenticity of to the Balts pantheon and the water sphere attributable deities Perdoytus, Wejopattis, Gardouten, Bangpjtjs, Luobgelda (partly Bardoayts) that were described in Matas Pretori­jus (Matthäus Prätorius) work “Sights of Prussia, Or Prussia’s Observation Place” (Deliciae Prussicae, oder Preussische Schaubϋhne) (the end of the 17th century). The focus of this article is on the analysis of authenticity Perdoytus (Gardouten ↔ Bardoayts) and opposition between Wejopattis ↔ Bangpjtjs mythologemes. In order to assess the validity of data the author uses in-depth comparative research whose core is in the comparison of the original and secondary material, allowing to determine who, when and what kind of mythical material changes were made. The study revealed that the mythical information provided by M. Pretorijus and other ancient written sources from XVI–XVII centuries are overshadowed by redundant and unauthentic information or interpretations of chroniclers. The author attempts to define this multi-level mental and physical phenomena by introducing a new term information noise in the verification process of ancient written sources.