The town of Adano is a fictional Sicilian port town modeled after the real town of Licata, one of the disembarkation town of the Allied Occupation of Italy. Just like Adano, the town of Licata has a shipping and sulfur industry, a fishing port, and its largest church is the Church of Sant'Angelo. Additionally, Benito Mussolini did have Licata's 700 year old bell melted to make ammunition. Major Joppolo is based on the American military governor of Licata named Frank E. Toscani. John Hersey visited Toscani for four or five days during the war and created Victor Joppolo from him, even noting that he held a job as a civilian clerk in the New York City Sanitation Department. General Marvin is an obvious depiction of the World War II General Patton, who was known for his bitterness and cruelty, but also his effectiveness.
Führer was the unique name granted by Hitler to himself, and this in his function as Vorsitzender (chairman) of the Nazi Party. It was at the time common to refer to party leaders as "Führer", yet only with an addition to indicate the leader of which party was meant. Hitler's adoption of the title was partly inspired by its earlier use by the Austro-German nationalist Georg von Schönerer, whose followers also commonly referred to as the Führer without qualification, and who also used the Sieg Heil-salute. Hitler's choice for this political epithet was unprecedented in German. Like much of the early symbolism of Nazi Germany, it was modeled after Benito Mussolini's Italian Fascism. Mussolini's chosen epithet il Duce or "Dux" if Latin ('the Leader') was widely used, though unlike Hitler he never made it his official title. The Italian word Duce (unlike the German word Führer) is no longer used as a generic term for a leader, but almost always refers to Mussolini himself.
After Hitlers' appointment as Reichskanzler (Chancellor of the Reich) the Reichstag passed the Enabling Act which allowed Hitler's cabinet to promulgate laws by decree. One day before the death of Reichspräsident Paul von Hindenburg Hitler and his cabinet issued a decree, that dissolved the office of the president and made Hitler Hindenburg's successor. However this move was in breach of the Enabling Act. Hitler adopted "Führer und Reichskanzler", combining his positions in party and government, as his title. Ostensibly Hitler did not use the title "president" out of respect for Hindenburg's achievements as a heroic figure in World War I (though the decree, rather impiously, was already passed before Hindenburg's death on August 2, 1934).
In popular reception, the title of Führer and Chancellor was soon understood to mean Head of State and Head of Government -- a view that becomes even more accurate seeing that he was given by propaganda the title of "Führer des deutschen Reiches und Volkes" (Leader of the German Reich and People), the name the soldiers had to swear to. However, it keeps some meaning as "Leader of Party and Head of Government" with reference to the confusing relationship of party and state, including posts in personal union as well as offices with the same portfolio Hitler wanted to fight for his favour. The style of the Head of State was changed on July 28, 1942 to "Führer des Großdeutschen Reiches" ("Leader of the Greater German Reich"). In his political testament, Hitler also refers to himself as Führer der Nation.
Nazi Germany cultivated the Führerprinzip (leader principle), and Hitler was generally known as just der Führer ("the Leader"). One of the Nazis' most-repeated political slogans was Ein Volk, ein Reich, ein Führer — "One People, One Nation, One Leader".
According to the Constitution of Weimar, the President was Commander-in-chief of the Armed Forces. Unlike "President", Hitler did take this title (Oberbefehlshaber) for himself. When conscription was reintroduced in 1935, Hitler had himself promoted to the new title Oberster Befehlshaber der Wehrmacht (Supreme Commander of the Armed Forces), which meant then a presidential position over the Wehrmacht in fact led by another (newly instituted) Commander-in-chief, the Minister for War. Following the Blomberg--Fritsch Affair in 1938, Hitler took the responsibilities of this commander-in-chief for himself, though he kept on using the older formally higher title of Supreme Commander, which was thus filled with a somewhat new meaning. Combining it with "Führer", he used the style Führer und Oberster Befehlshaber der Wehrmacht ("Leader and Supreme Commander of the Wehrmacht"), yet a simple "Führer" since May 1942.