The phrase "white slavery" was used by Charles Sumner in 1847 to describe the chattel slavery of Christians throughout the Barbary States and primarily in the Algiers, the capitol of Ottoman Algeria. It also encompassed many forms of slavery, including the European concubines often found in Turkish harems. The term was also used from the beginning of the twentieth century when most of the countries of Europe signed in Paris in 1904 an International Agreement for the suppression of the White Slave Traffic aimed at combating the sale of women who were forced into prostitution in the countries of continental Europe. In the early twentieth century, the term was used against the forced prostitution and sexual slavery of girls who worked in Chicago brothels.