Protestant monk F.A. Larson first visited Mongolia in 1893 when he was 23 years old. Since then, he visited Mongolia many times until the 1940s, studying Mongolian languages, learning the history Mongolian and collecting a substantial amount of material about Mongolian traditional life and culture. He not only made a close observation of the major political events in Mongolia in the early 20th century, but also participated in some of these events. In recognition of his work for Mongolia, Bogd Khan gave him a "duke" title. At the request of R.C. Andrews, he was part of the” Comprehensive Survey of Asia" by the American Museum of Natural History. Later, he wrote many interesting books and memoirs about Mongolia and Mongolians.