Achiri mudiki, Hartleben akarerwa nasekuru vake muHannover. Pakati pevadiki vake vaiziva vaive Karl Henckel, Arthur Gutheil uye ramangwana muindasitiri uye wezvematongerwo enyika Alfred Hugenberg uye pamwe chete vakaburitsa vhoriyamu yenhetembo Quartett muna 1886. Mushure mekupedza chikoro chake muCelle muna 1886 akaenda kunodzidza mutemo, kutanga kuLeipzig, kwaakasvika pakuziva Hermann Conradi naAdolf Bartels, uye gare gare muBerlin. Akadzidza basa rehurumende muStolberg (Harz) uye muMagdeburg. Achisiya zvidzidzo zvake zvemutemo, akadzokera kuBerlin kwaakashanda semunyori akazvimiririra, akazopedzisira aenda kuMunich muna 1901.
Karl Henckel, Arthur Gutheil