Only in the south it is less naturally protected, about 400 meters above sea level. At that time, this terrain offered enough space for building houses, cultivating gardens and fields, protection from advancing enemies, as well as the vital water.
The first evidence of human life was found in the form of flint blades near the site from about 14,000 BC. Ceramic fragments of the Neolithic Michelsberg culture, found in the area of the Stiftskirche, suggest a hilltop settlement in the 4th/3rd millennium BC. Excavations, also in the vicinity of the Stiftskirche, uncovered remains of a wooden earthen rampart, which can be dated to the pre-Roman Iron Age as part of a rampart castle, around the 5th/4th century BC. In the "Frankish Annals" the place was called "Eresburg". The Eresburg belonged to the Saxons. However, it was conquered in 772 AD by Charlemagne with his Franks, lost again and reconquered. He destroyed the sanctuary of the Saxons, the Irminsul, built a church in its place and established a Benedictine convent. For the winter of 784/785, a stay of several months by Charlemagne at Eresburg is documented. In 826, Louis the Pious, a son of Charlemagne, donated the Eresberg with the monastery to the Corvey monastery founded by him.