The first traces of human presence in Fassa Valley date back to Mesolithic (ca. 8000-5000 b.C.), when hunters coming from the Po valley started to penetrate through the alpine passes and the vast grasslands, no more covered in ice due to the glaciers withdrawal, searching for game to hunt. Witnesses of their passage have been observed in different places in Fassa Valley. However the permanent presence of humans dedicated to farming and breeding started only in Neolithic, as witnessed by the archeologic finds found in Mazzin and Campitello, which date back to Bronze age (1800-900 b.C.). Archeologists agreed the presence of a cultural unit of people in the dolomites since the Iron II age (600 b.C). The archeologic finds of a Raetian “Castelliere” on the Col of Pigui, near Mazzin, support this thesis. Raeti were a mysterious people with unknown origin. They left various traces of their rural civilization in an area that extended from the sources of river Reno, to the Inn valley, from the Adige valley to the dolomitic area. The “castelliere” of Mazzin actually represents a typical fortified Raetic resettlement. Basically it is a small village, surrounded by a solid defense wall, inside which there were the houses made of wood. Many furnishings and fittings made of ceramic, mills, jewels and heads of javelin have been found in there. Raeti were organized in different tribes of shepherds and farmers, tied to cultural and language ties. Raetic civilization was subjugated by Romans forces after the military conquest of the entire reagion by senior commanders Drusus and Tiberius in 15 BC. The annexation of Raetia to the Roman Empire brought the latin language to the Raeti tribes from which, during the centuries, the ladin (or “retromanzo”) language originated. Traces of the Raetic substrate still exist in the toponymy, even if ladin language has known a deep evolution due to near languages, in particular the Tyrolean and north-italian dialects.