 Beginning in the 1890s, the majority of the mission's members campaigned for mission expansion into the Shan States of Burma, which brought it into a protracted, time-consuming territorial dispute with the American Baptists in Burma.For a brief period from 1911 to 1914, the mission's church grew rapidly in the wake of malaria and smallpox epidemics in various parts of northern Siam.With improvements in communications between northern and central Siam, the Laos Mission was united with the Siam Mission in 1920-21.