Since China was initially the favorite field of activity of the C.I.C.M. founded at Scheut (a suburb of Brussels) in 1862, it is not surprising that the oldest documents in its archives refer to the China missions. In 1888, however, three years after the establishment of the Independent State of the Congo, the first C.I.C.M. missionaries were sent out there and their successors still continue their activities. Thus nowadays a very important part of the archives concerns the Congo, covering a period of nearly ninety years.
At first the Apostolic Vicariate entrusted to the C.I.C.M. missionaries covered the entire extent of the Congo except for parts of the Apostolic Vicariate of Tanganyika, created two years earlier and given to the White Fathers to administer. Gradually, however, other missionaries came to help the C.I.C.M. pioneers and were put in charge of various territories which had originally been part of the Apostolic Vicariate. Eventually the C.I.C.M. retained only Leopoldville and its surrounding area, and the regions of Lower Congo, Equator, Lake Leopold II, and Kasai which, from the religious point of view, gave rise to the present C.I.C.M. provinces of Kinshasa, Boma, Lisala, Budjala, Inongo, Kananga, and East Kasai. This dismemberment explains why the documents preserved in the archives become more and more concentrated on these regions.