In 1914, together with the core of Casentinesi Forests complex, the territory of the current Sasso Fratino Nature Reserve became part of the State Owned Forest Heritage. In 1959, the first nucleus of about 110 ha was closed to free access and any kind of measure was precluded. Sasso Fratino Nature Reserve is the first Strict Nature Reserve to be established in Italy according to the classification of IUCN (International Union for the Conservation of Nature). Therefore, the protection of nature regards here any vegetable and animal species, rocks, soil, waters, and air. On September 23, 1985 Sasso Fratino Nature Reserve was awarded with the European Diploma.