 In December 1862, Peruvian slave raiders took between 1,400 and 2,000 islanders back to Peru to work in the guano industry; this was about a third of the island's population and included much of the island's leadership, the last "ariki-mau" and possibly the last who could read Rongorongo.After intervention by the French ambassador in Lima, the last 15 survivors were returned to the island, but brought with them smallpox, which further devastated the island.Slavery has existed, in one form or another, throughout the whole of human history.