The files on the Ministry of External Affairs housed in the Institute of Modern History, Academia Sinica, mainly cover the period from 1901 to 1911. A few files either pre-date or post-date this period because during the archiving process some files belonging to the same categories but different foreign offices were not separated out. This decision was made for sake of reading consistency. The files are divided into thirty-seven categories, according to subject matter and include arms, mining, Boxer Protocol in 1901, Macao files, and files originally kept at the embassy in the US, etc.