The Hardee hat, also known as the Model 1858 Dress Hat and sometimes nicknamed the "Jeff Davis", was the regulation dress hat for enlisted men in the Union Army during the American Civil War. The Hardee hat was also worn by Confederate soldiers. However, most soldiers found the black felt hat to be too hot and heavy and shunned its use, preferring a forage cap or slouch hat. However, the unadorned, plain and often field-modified Hardee hat was worn by Union troops, especially in the Western theater. The hardee hat was most famously worn, and easily identified, as the hat worn by the Union Army's Iron Brigade, which became their trademark and were popularly known, by the nickname, "The Black Hats".