The dutch colonial power in Indonesia in the nineteenth century needed to clarify its understanding of legal values and conventions of the peoples whom it claimed to rule. Dutch colonial lawyers tended to rationalize this legal culture, lumping together all kind of indigenous legal customs fro different areas as manifestations of adatrecllt, or costomary law. The status of this legal system vi-a-vis Dutch colonial law was a source of continual debate and disagreement. The champions af adatrecht, known as the Leiden School, with C. van Vollenhoven in the forefront, scored a victory around 1927 when adatrecht gained official recognition, though on the other hand it became the subject of mounting criticism. After World War 11, the independent state of Indonesia paid lip service to adatrecht principles, but in practice treated it as irrelevant, or even an embarrassment. Peter Burns, a retired Australian academic, describes the debate and analysis the rise, development and fall of the concept of adatrecht, which is so closely connected with the Leiden University and the KITLV.