This paper is a study of the Swedish fornborg Torsburgen on Östergarnslandet, Gotland. This is the largest fornborg on Gotland and it has an area of 112 hectares. The northern, eastern and western parts of the plateau, on which Torsburgen is lying, has natural cliffs of up to 30 meters, while there in the southern part is a two-kilometer-long wall. During the 1980´s a part of the wall was excavated in an attempt to date the construction. The conclusion was, that it had many different building stages. The earliest find was dated to the later Roman Iron Age (AD 200-400) and that period is therefore also the focus of this paper.  The aim of this paper is to explain different hypotheses of why this wall was built (for what reason) and what purpose did it fulfill in society. Archaeological finds from Gotland, dated to the period of the later Roman Iron Age, often show connections to the Roman Empire and therefore the construction could be a result of influences from that part of the world.  It is however, with today’s knowledge, not possible to point out one specific reason why the wall of Torsburgen was built and for what reason they needed to fortify the area of 112 hectares. It could have been an invading force, but it could just as likely have been a need of a hideout to protect the inhabitants on the island from an invading force. Other hypotheses are that it could have been a place for religious practice or a hideout for exiled people, which some people claim that an episode in the Gotlandic legend Gutasagan is about. Hopefully archaeological finds in the future could lead to new knowledge and maybe result in an answer of why this monument is standing there.

This paper deals with hill-forts located on and directly south of Selaön, in the center of Mälardalen, Södermanland, dated to the late roman period and the migration period. Of special interest is differences and similarities between the forts when it comes to their morphology and the hills where they were built. Furthermore, their landscape has been examined and I have tried to put the hill-forts in relation to any iron age settlements.