There had been settlement on this part of the Abens river since long before the High Middle Ages, dating back to Neolithic times. Of particular interest and national importance are the Neolithic flint mines at Arnhofen, where, around 7,000 years ago, Stone Age people made flint, which was fashioned into drills, blades and arrowheads, and was regarded as the steel of the Stone Age. Traces of over 20,000 individuals were found on this site. The modern history of Abensberg, which is often incorrectly compared with that of the 3rd century Roman castra (military outpost) of Abusina, begins with Gebhard, who was the first to mention Abensberg as a town, in the middle of the 12th century. The earliest written reference to the town, under the name of "Habensperch", came from this time, in around 1138. Gebhard was from the Babonen clan.