Yolngu art became recognized as art in the wider world through the process of its commercialization. Yolngu society only opened up to the Euro-Australian world in the 1920s and 1930s – before then the art of the region was virtually unknown. There are probably no hidden collections of it waiting to be discovered in the basements of some European Museum. Time or timing has also been important in another respect. In the 1930s Australia was just beginning to come out of an era in which Aborigines had been excluded from Australian society. The rights of Aboriginal people had been gradually eroded away. The Gängan massacre signalled the beginning of more intensive contact with outsiders. The Macassans no longer visited the Arnhem Land coast: they had been effectively prevented from visiting the shores by the imposition of a regime of high taxation.