Based on ethnological analysis, the author of this article presents a new hypothesis concerning the currently obscure origin of the tradition of decorating roadside crosses with aprons and ribbons in the area of the Southern Highlands in Lithuania. Due to an identical and prevalent tradition among the Belarusians, the phenomenon is ascribed to cultural innovations of non- Baltic origin. This enables the identification of the genesis of the custom, for up to the present time the most archaic reminiscenses of proto-Semitic religious-mythological models were interpreted as authentic factographic relics of the Baltic proto-culture: the transformation of mythological images, reflection of necroculture, fertility rites, etc.