Fort Niagara became a prisoner of war camp on June 12, 1944, housing Axis captives taken as Allied victories increased in World War II. One of 500 such camps in the United States, it served as the central command post for 13 branch camps across western and central New York. Although it could hold up to 3,000 prisoners, no more than 2,200 were there at one time. Prisoners worked on farms and in food processing plants to help meet labor shortages, and they were treated fairly, with opportunities to organize their own school, orchestra, choir, sports activities, and artistic pursuits. Fort Niagara began releasing prisoners in late 1945, and some remained until 1946. Among those held there was Ernst Wills, born on September 28, 1916, who was captured by Canadian forces on D-Day, June 6, 1944, during the Allied invasion of France. While imprisoned at Fort Niagara, he painted a mural titled American History for the Bachelor Officer Quarters and also painted portraits of officers and inmates there. After the war, he achieved success as an artist in Europe, and American culture, especially jazz music, influenced his painting style.