Answer: According to the book With Alex at War, the autobiography of Sir Rupert Clarke, the monastery at Monte Cassino in Italy, was destroyed during the second world war because of a translation mistake by a British junior officer. According to an article published in The Guardian - "Error led to bombing of Monte Cassino" (see https://www.theguardian.com/world/2000/apr/04/johnezard ):

"The officer - translating an intercepted radio message - mistook the German word for abbot for a similar word meaning battalion. His version convinced his superiors this meant a German military unit was using the monastery as its command post, in breach of a Vatican agreement which treated it as neutral."

"Tragically, this was discovered too late," the book says. "The bombers were already approaching."

Another article on this subject can be found at: https://www.nationalww2museum.org/war/articles/destruction-of-monte-cassino-1944

Vatican Notes has several articles about the Monte Cassino:
 • James C. Hamilton, St. Benedict: From Subiaco and Monte Cassino to Patron of Europe, Vatican Notes, Volume 60 Issue 351 2012, Pages 10-18
 • Rev. H. A. Phinney, The Abbey Of Monte Cassino, Vatican Notes, Volume 17 Issue 6, 1969, Pages 10 - 12


St. Benedict & The Abbey Of Monte Cassino
Scott # 414-415 (1965)