 Andrić spent the following three years in a friend's Belgrade apartment in conditions that some biographers liken to house arrest.In August 1941, the puppet authorities in German-occupied Serbia issued the Appeal to the Serbian Nation, calling upon the country's inhabitants to abstain from the communist-led rebellion against the Germans; Andrić refused to sign.He directed most of his energies towards writing, and during this time completed two of his best known novels, "Na Drini ćuprija" ("The Bridge on the Drina") and "Travnička hronika".