A small fringe group of the Dani, living south of Puncak Trikora and presenting themselves as the Pesegem and the Horip tribes, were met on October 29, 1909, by the Second South New Guinea Expedition led by Hendrikus Albertus Lorentz, who stayed several nights in their village. First contact with the populous Western Dani was made in October 1920 during the Central New Guinea Expedition, which group of explorers stayed for six months with them at their farms in the upper Swart River Valley (now Toli Valley). The Grand Valley Dani were only sighted in the summer of 1938 from an airplane by Richard Archbold.