Daniel Sickles was a Union general during the American Civil War, known for his controversial actions and leadership. Born on October 20, 1819, in New York City, he served in the Mexican-American War before entering politics. Sickles gained fame for his role in the Battle of Gettysburg, where he made a significant but risky decision to advance his troops, leading to heavy casualties. In addition to his military career, Sickles was involved in a notorious scandal in 1859 when he killed his wife's lover, Philip Barton Key, the son of Francis Scott Key. He was acquitted of murder, becoming one of the first to successfully use the temporary insanity defense in the United States.