Frédéric Ozanam was born on April 23, 1813 in Milan, Italy. He was the fifth child of fourteen born to Jean-Antoine-François and Marie Nantas Ozanam, ardent French Catholics of middle-class circumstances. His father had served with distinction as an officer under Napoleon, retiring early to become a tutor and later to practice medicine. When the city of Milan fell to the Austrians in 1815, the Ozanams returned to their native city of Lyon, where Frédéric spent his early years.