Kuikuro oral history says Portuguese slavers arrived in the Xingu region around 1750. Xinuguano population was estimated in the tens of thousands but was dramatically reduced by diseases and slavery by Portuguese. In the centuries since the penetration of the Europeans into South America, the Xingu fled from different regions to avoid the spread of deadly disease and enslavement by the Portuguese. By the end of the 19th century, about 3,000 natives lived at the Alto Xingu, where their current political status has kept them protected against foreign intruders. By the mid twentieth century this number had been reduced by foreign epidemic diseases such as flu, measles, smallpox and malaria to less than 1,000. Only an estimated 500 Xingu peoples were alive in the 1950s.