The settlement of Easter Island has been a topic of considerable conjecture and debate. Thor Heyerdahl's Kon-Tiki expedition showed that the island could have been settled from South America, although linguistic and archaeological evidence suggests settlement from other Polynesian islands Perhaps as early as A . D . 400. Wherever the first Easter Islanders migrated from, it is likely that, given the remote location of the island, they were relatively isolated from other Polynesians. First contact with Europeans was with the Dutch explorer Jacob Roggeveen in 1722. There is some evidence that because of deforestation and wars between subtribes, the population was already declining and the culture disintegrating at this time. The island was subsequently visited, usually infrequently and briefly, by a succession of Spanish, English, French, American, and Russian explorers, traders, and whalers. The first major and the most significant contact occurred in 1862 when Peruvian slavers raided the island and kidnapped about 1,000 men to the guano islands off the Peruvian coast. There the Easter Islanders were forced to mine guano for one year during which time 900 died. Facing an international scandal, the Peruvian government sent the remaining 100 men home, although only 15 survived the trip. Infected with smallpox, they spread the disease to those on the island, further reducing the population to perhaps 25 percent of what it had been in 1862. The depopulation, disease, fear of outsiders, and death of many leaders led to cultural disintegration and a loss of much of the traditional culture within a decade. Catholic missionaries arrived in 1863, beginning a small though continuous European presence to this day. Within ten years, all surviving Easter Islanders were converted to Roman Catholicism, with many of the economic and social practices taught by the priests replacing traditional culture practices. In 1888 Chile annexed the island and subsequently leased 160 square kilometers to the Williamson and Balfour Company, which established sheep ranching for wool. The remaining 20 square kilometers were set aside for use by the Easter Islanders. In 1954 governance of the island and the sheep-ranching business was turned over to the Chilean navy, and in 1965, in response to islander complaints, the island was put under civilian control. Easter Island is Currently a dependency of Chile and Easter Islanders are Chilean citizens.