One hundred years ago the terrible WWI Battle of Caporetto began (on Oct. 24). The battle was named for a town that is now in Slovenia (and is called Kobarid in Slovene) and that used to be in Yugoslavia, in Italy, in Austria-Hungary, etc.
Caporetto was the 12th Battle of the Isonzo, the last in a series of costly and generally poorly planned attacks in difficult mountain terrain.
It was a cataclysmic defeat for the Italians that nearly knocked them out of the War. What the Somme is for the British and Canadians, and what Verdun is for the French and Germans, Caporetto is for the Italians.
One of the young men on the Italian side of this battle was Angelo Giuseppe Roncalli (aka Pope John XXIII), who was a chaplain (according to his German Wikipedia entry). Among the Italian soldiers to be killed at Caporetto was the mathematician Eugenio Elia Levi.
Like other major WWI engagements, Caporetto's cultural ramifications reverberated for many years after the War and include important literary works by people who were swept up in the battle or its aftermath. In English there's Hemingway's A Farewell to Arms, which describes the Italian retreat and derives partly from the author's experiences with a volunteer ambulance service in Italy about six months after Caporetto.
In Italian, there's Curzio Malaparte's Viva Caporetto! (for which I can't find an English trans.). Emilio Lussu's memoir, Un anno sull'Altipiano, covers the battle and has been translated into English (as A Soldier on the Southern Front). Novelist and engineer Carlo Emilio Gadda was taken prisoner at Caporetto, an experience which he describes in his Giornale di guerra e di prigionia (or War and Prison Diary, unavailable in English). While a POW, Gadda befriended two other literary prisoners from Caporetto, Ugo Betti and Bonaventura Tecchi. I don't know if these last two authors published anything explicitly about their WWI experiences.
Umberto Rossi has written about Caporetto's traces in Italian literary culture.
Rai has a short video about the battle.
The Italians faced an attacking force of Germans and Austro-Hungarians. Erwin Rommel led part of the German group. The Hapsburg troops included many Slovenes, Croatians, Bosnian Muslims, and Hungarians. Among the Hapsburg officers at Caporetto were Ludwig von Mises and the composer Viktor Ullmann, who survived WWI but was murdered at Auschwitz Oct. 18, 1944.