From Wikipedia
Treaties formed an important part of European colonization and, in many parts of the world, Europeans attempted to legitimize their sovereignty by signing treaties with indigenous peoples. In most cases these treaties were in extremely disadvantageous terms to the native people, who often did not appreciate the implications of what they were signing.
In some rare cases, such as with Ethiopia and Qing Dynasty China, the local governments were able to use the treaties to at least mitigate the impact of European colonization. This involved learning the intricacies of European diplomatic customs and then using the treaties to prevent a power from overstepping their agreement or by playing different powers against each other.
In other cases, such as New Zealand and Canada, treaties allowed native peoples to maintain a minimum amount of autonomy. In the case of indigenous Australians, unlike with the M?ori of New Zealand, no treaty was ever entered into with the indigenous peoples entitling the Europeans to land ownership, under the doctrine of terra nullius (later overturned by Mabo v Queensland, establishing the concept of native title well after colonization was already a fait accompli). Such treaties between colonizers and indigenous peoples are an important part of political discourse in the late 20th and early 21st century, the treaties being discussed have international standing as has been stated in a treaty study by the UN.