In the aftermath of the Peruvian slave deportations in the 1860s, Rapa Nui came under extensive outside influence from neighbouring Polynesian languages such as Tahitian. While the majority of the population that was taken to work as slaves in the Peruvian mines died of diseases and bad treatment in the 1860s, hundreds of other Islanders who left for Mangareva in the 1870s and 1880s to work as servants or labourers adopted the local form of Tahitian-Pidgin. Fischer argues that this pidgin became the basis for the modern Rapa Nui language when the surviving part of the Rapa Nui immigrants on Mangareva returned to their almost deserted home island.