Burma, in the mid-nineteenth century was bounded on the east by China and Siam, and on the west by Assam and Bengal. Its area was approximately 444,001 km², while that of Great Britain and Ireland is 310,798 km², but it's not densely populated. For some ten years the mission remained under the administration of the Vicar Apostolic of Siam; but such a condition could not be indefinitely prolonged without compromising its future. A decree of Propaganda Fide on 27 November 1806, accordingly divided Burma into three vicariates, named respectively with references to their geographical positions, Northern Burma, Southern Burma, and Eastern Burma. The boundaries then fixed were abrogated on 28 June 1870, by another decree of Propaganda, which constituted these three vicariates as they now are.