The settlement at Grobin was excavated by Birger Nerman in 1929 and 1930. Nerman found remains of an earthwork stronghold, which had been protected on three sides by the Ālande River. Three Vendel Age cemeteries may be dated to the period between 650 and 800 AD. One of them was military in character and analogous to similar cemeteries in the 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". From Nerman's findings, it appears that Grobin was the site of an early Scandinavian colony from Gotland. Many of the graves in level ground were of women, who could be identified as natives of Gotland by their belt-buckles and brooches. The grave-mounds predominantly housed men, often accompanied by typical Scandinavian weaponry.