during the 6th millennium BC. This changed only in the middle and late Neolithic when shore settlements were established, the so-called pile dwelling and wetland settlements, which have now been uncovered mainly on Lake Überlingen, the Constance Hopper and on the Obersee. At Unteruhldingen, a pile dwelling village has been reconstructed, and now forms an open air museum. In 2015, a 20 km line of about 170 man-made dated in the neolithic period or early bronze age were discovered on the south-west shore of the lake between Bottighofen and Romanshorn. Grave finds from Singen am Hohentwiel date to the beginning of the Early Bronze Age and shore settlements were repeatedly built during the Neolithic Period and the Bronze Age (up to 800 BC). During the following Iron Age the settlement history is interrupted. The settlement of the shore of Lake Constance during the Hallstatt period is attested by grave mounds, which today are usually found in forests where they have been protected from the destruction by agriculture. Since the late Hallstatt period, the peoples living on Lake Constance are referred to as the Celts. During the La Tène period from 450 BC, the population density decreases, as can be deduced partly due from the fact that no more grave mounds were built. For the first time, written reports on Lake Constance have survived. Thus, we learn that the Helvetians settled by the lake in the south, the Rhaetians in the area of the Alpine Rhine Valley and the Vindelici in the north-east. The most important places on the lake were Bregenz (Celtic Brigantion) and today's Constance. In the course of the Roman Alpine campaign of 16/15 BC, the Lake Constance region was integrated into the Roman Empire. During the campaign, there was also supposed to have been a battle on Lake Constance. The geographer, Pomponius Mela, makes the first mention in 43 AD of Lake Constance as two lakes – the Lacus Venetus (Upper Lake) and the Lacus Acronius (Untersee) – with the Rhine flowing through both. Pliny the Elder referred to Lake Constance as Lacus Brigantinus for the first time. The most important Roman site was Bregenz, which soon became subject to Roman municipal law and later became the seat of the Prefect of the Lake Constance fleet. The Romans were also in Lindau, but settled only on the hills around Lindau as the lakeshore was swampy. Other Roman