In Friuli, during the First World War, the line from Mount Peralba (Piave Springs) to Montemaggiore (Sources Natisone), including the valleys of the High tagliamento, Degano, But and Fella, was known as Zona Carnia. The strategic value of this sector stemmed from the fact that being the link between the Armed deployed to his left (Cadore and Trentino) and those on his right (Julian Pre-Alps and Karst), was considered by the General Staff of Vienna, the door leading to Italy.
In support of this strategy, since the beginning of ’900 was built a chain of military works that took the name of Fortress Alto Tagliamento or Ridotto Carnico composed by the forts of Chiusaforte, Monte Festa, Osoppo and Ospedaletto Monte Ercole.
The Zone Carnia, in which were located at the beginning of the war 31 battalions, including 16 alpine, and many units of artillery and engineers, saw fierce fighting in the mountainous area of the sector But, from Monte Peralba to Monte Cullar (Monte Avanza , Monte Coglians, Pal Grande, Pal Piccolo, Freikofel, Monte Zermula and Passo Lanza). The various departments including 2 Alpini battalions of local recruitment, Tolmezzo and Val Tagliamento, have fought and defended the mountain tops also thanks to the invaluable support of the Carnic woman Portatrici Carniche, until the end of October 1917, the date on which, after to the 12th battle on Isonzo defeat of Caporetto, happened the heroic episode of the defense of Mount Festa, and the equally heroic defense made by the Italian services in Resia.