McKinley was the last president to have served in the American Civil War and the only one to have started the war as an enlisted soldier, beginning as a private in the Union Army and ending as a brevet major. After the war, he settled in Canton, Ohio, where he practiced law and married Ida Saxton. In 1876, he was elected to Congress, where he became the Republican Party's expert on the protective tariff, which he promised would bring prosperity. His 1890 McKinley Tariff was highly controversial, which together with a Democratic redistricting aimed at gerrymandering him out of office led to his defeat in the Democratic landslide of 1890. He was elected Governor of Ohio in 1891 and 1893, steering a moderate course between capital and labor interests. With the aid of his close adviser Mark Hanna, he secured the Republican nomination for president in 1896 amid a deep economic depression. He defeated his Democratic rival William Jennings Bryan after a front porch campaign in which he advocated "sound money" (the gold standard unless altered by international agreement) and promised that high tariffs would restore prosperity.
Millions of $500 dollar bills were printed in US, mostly before 1940s. Believe it or not, but $500 dollar bills are still very common. The collector value of five hundred dollar bill is generally around 1.5x to 2x the value printed on the bill.