Walter Baldwin Spencer was invited to participate as zoologist and photographer in the Horn Scientific Expedition, the first primarily scientific expedition to study the natural history of Central Australia. The expedition took place from May to August 1894. At the end of the Expedition, at Alice Springs in July of 1894, Spencer met Frank J. Gillen, the operator of the Alice Springs Telegraph Station. Gillen had for many years maintained an interest in and concern for the Arrernte Aboriginal people. In 1901 Spencer and Gillen set out on an expedition together, whose purpose was to study the Arrernte people, establish 'intimate relations with the natives' and study other groups between the Arrernte and the north coast. At Barrow Creek, about 280 km north of Alice Springs, Spencer encountered members of two groups, the Anmatyerr and the Kaytetye, both similar in appearance and social organisation to the Arrernte, but smaller in numbers. The Anmatyerr inhabiting the land around Central Mt Stuart on the northern boundary of Arrernte land was, according to Spencer 'now nearly wiped out, partly by drought and partly by the fact that they had, years ago, been what is called "dispersed", after having attacked one or two white men whose intrusion into their country they resented, with results unfortunate to themselves'.