The genus Castor first appeared in the Palaearctic region during the Late Miocene, while the current species, Castor fiber , is widely accepted to have emerged in the Early Pleistocene. In the Last Glacial Maximum (Late Pleistocene), the beaver disappeared from most of the Western Palaearctic, only surviving in a few relic areas including the south-eastern Alpine Chain as shown by new data. After the subsequent extended repopulation in the warmer phases of the Lateglacial and in the early Holocene, the species once again disappeared locally from several countries, including Italy, between the 17th and the 20th centuries. Direct or indirect persecution by humans seems to be the main cause of beaver extinction in Europe. In Low Medieval Italy, it is more likely that the disappearance of the beaver between the 16th and 17th centuries was due to habitat alteration and human population pressure. Numerous reclamations have been carried out since the late Middle Ages, mostly in the easternmost area of the Po Valley, the last beaver refuge in Italy. Eurasian beaver was common in the northern and widespread in the central part of Italy, but always absent in southern Italy, probably due to unfavourable hydrological conditions of watercourses in the latter.