Antoine Amedee Marie Vincent Manca de Vallombrosa was born on June 14, 1858 in Paris, France. He was well educated and had a career in the French military prior to his time spent in Dakota Territory. Descending from French, Sardinian, and Spanish nobility, he later acquired the title Marquis de Mores. On February 15, 1882 de Mores married Medora von Hoffman, the daughter of a Wall Street banker in Cannes, France. After spending time in New York City, de Mores became interested in the cattle industry and Dakota Territory. Named after his wife, de Mores established Medora in Billings County in April of 1883. Between 1883 and 1886, Medora was the center of the Marquis’ beef enterprise. As a result of significant financial loss, the de Mores family departed from Medora in 1886 and returned to France in 1887.