5. Philippe Petain
French Marshal Philippe Petain fought the Germans and collaborated with the same in the two different world wars. While he is popularly remembered to have collaborated with Germany during the 2nd World War, he actually headed the troops that fought and repulsed the German attack at Verdun in World War 1 (1916). This made him a national hero.
He had a stint as Commander in Chief, a position he used to enhance discipline in the French military. He also helped raise their morale at a time when this was most needed to be able to withstand the great German offensive of spring 1918.
4. Douglas Haig
Douglas Haig was a British Field Marshal. He replaced John French in late 1915 as Commander in Chief of the British Expeditionary Force, BEF, and held the position until the end of World War 1. He led the British troops in the Somme Offensive in 1917 and a year later in the Battle of Passchendaele. Even though both of the battles suffered massive casualties, General Haig is remembered to have played a key role in the Allied victory over the Central Powers.
3. Armando Diaz
He was an Italian general and Field Marshal born in Spain. Armando Diaz served as corps commander of the Italian forces after being promoted from the position of major-general under Luigi Cadorna.
He replaced Cadorna as Italian Army’s Chief of Staff after the tragedy at the Battle of Caporetto in the fall of 1917. In 1917 he repulsed the Austro-Hungarian offensive and launched a counter-offensive that achieved a decisive victory over the Austria-Hungarians. He also led the Italians to a great victory in the June 1918 Battle of the Piave River. This was followed a few months later by yet another decisive victory in the Vittorio Veneto War that ended World War I on the Italian Front.