The name "Proselko" has an unclear origin and motivation. This personal name belongs to the Slavic names of the 15th century. For example, in a document it is mentioned: "that land of Proselkova and Martyntsiv, which his father Ostafiy gave to Proselko, we have awarded to Bohdan Ostafiyovych," — the city of Vilna (SSUM II 262).
