Complex sentence: The territory of the Congo was invented by Belgian colonial rulers that borrowed the name used by the historic Kongo Kingdom, however at the time there was no conception of a Congolese people-they were divided into ethnic and tribal groups.
Split into simpler sentences: The territory of the Congo was created by Belgian colonial rulers that borrowed the name used by the historic Kongo Kingdom. At the time there was no concept of a Congolese people however, as the people living within the region were divided into ethnic and tribal groups.