The Viking settlement at Grobin was excavated by Birger Nerman in 1929 and 1930. Nerman found remains of an earthernwork stronghold, which had been protected on three sides by the Alanda River. To the period between ca. 650 and ca. 800 may be dated three Vendel Age cemeteries, one of them military in character and analogous to similar cemeteries in Mälaren Valley in Central Sweden, while two others indicate that there was "a community of Gotlanders who were carrying on peaceful pursuits behind the shield of the Swedish military".