 He also pioneered the research of Kashubian culture and collected many Slavic artifacts from Masuria.He translated into Polish such works as "Anabasis".Mrongovius was a member-correspondent of the Society of Friends of Science in Warsaw (from 1823) (approved by acclamation), Gesellschaft für Pommersche Geschichte und Altertumskunde in Szczecin (from 1827) and member-correspondent of the Kraków Scientific Society ("Towarzystwo Naukowe Krakowskie") (from 1833).