Frederick Knefler (Knoepfler Frigyes) was born in Arad, Hungary, son of Nathan Knoepfler, a Hungarian Jew and a physician. He enlisted with his father in the revolutionary forces during the 1848-49 Hungarian War of Liberation. After the revolutionary forces were defeated, the entire Knoepfler family fled to the United States, first to New York, then to Indianapolis, Indiana. As one of the earliest Jewish families settling in Indianapolis, Dr. Knoepfler was one of the original founders of the Indianapolis Hebrew Congregation.