However, during the 19th century, Western European colonial powers were involved in the suppression of the Arab slave trade in Africa, as well as in the suppression of the slave trade in West Africa. Some Europeans during the time period objected to injustices that occurred in some colonies and lobbied on behalf of aboriginal peoples. Thus, when the Hottentot Venus was displayed in England in the beginning of the 19th century, the African Association publicly opposed itself to the exhibition. The same year that Kipling published his poem, Joseph Conrad published "Heart of Darkness" (1899), a clear criticism of the Congo Free State, which was owned by Leopold II of Belgium.