Stone artefacts indicate that humans frequented the area from the
Ice Age to the 3rd millennium BC. There is some evidence that the area was inhabited since the
Neolithic period. However, findings make it more likely that it was not used for settlement by Neolithic farmers but for gaining access to . There is just one grave dating to the middle
Bronze Age (1600-1300 BC) but several graves nearby date to the late Bronze Age and some burial mounds (with wooden chambers) are from the early
Iron Age. In several locations settlement remains contemporaneous to the necropolis (late
Hallstatt period and early
La Tène period) have been found in the area that later became the Heidengraben. The
Heidengraben was likely created in the late La Tène period (late 2nd century BC to early 1st century BC). However, in the period of 250 to 150 BC the area seems to have been once again unpopulated. Archaeological findings indicate the presence of a simple agricultural population as well as specialized artisans (metal working, glass production). In addition, a large number of shards from Roman
amphorae dating to 130 to 90 BC indicate that a significant amount of Roman wine was imported. This implies the existence of a rich elite that could afford these luxury items. No evidence of a burial site dating to the
oppidum period has been discovered, but the earlier necropolis seems to have been used as a cult site and possibly for burial rituals. Why and exactly when the settlement was abandoned remains unclear. It appears that the inhabitants left it in the first half of the 1st century BC, but there is no indication of any reasons. This dating fits in with the abandonment of other oppida in that era, pointing to some fundamental changes in social, economic or political circumstances. Around 85 AD the
Romans occupied the Swabian Jura and there were some farms or
mansiones in the area. The Romans left c. 260 AD. The next signs of inhabitants date to the 7th century, when the area was settled by
Alemanni. In the Middle Ages the area was only sparsely inhabited but some castles were constructed nearby like
Hohenneuffen Castle (early 12th century) or Burg Hofen east of Grabenstein. The purpose of a medieval fortification surrounding 55 hectares to the north of
Heidengraben (known as
Bassgeige) is still unknown. It incorporates parts of a Celtic wall but was extended in late medieval times. Several similar structures nearby (
Brucker Fels and
Beurener Fels) also served an unknown purpose. ==Research==