 In 1928–1929, Volters briefly surveyed Apuolė and, during a conference of Baltic archaeologists in Riga in August 1930, convinced Swedish professor Birger Nerman to organize and finance large scale excavations of Apuolė hill fort and tumulus in 1931.From the Lithuanian side, the excavations were supervised by .In 1930, in preparation for the 500th death anniversary of Grand Duke Vytautas, Volters supervised excavations and other works at the Kaunas Castle.