Where does the concept of human trafficking come from?

Although the concept of “white slave trade” is circumscribed to a specific type of exploitation (sexual) and victims (women), it is still common that people misuse this expression to make reference to human trafficking.
It was in England, in the late nineteenth century, when this expression was firstly used by groups of people working to end prostitution and transportation of European women and girls for sexual exploitation.
In several European countries, the activism of these groups generated a wide range of governmental responses. For many organizations, the idea of having an international legal framework against “white slavery trade” became a cornerstone. This ambition was accomplished at the entry of the twentieth century.
The first international instruments were focused on the sexual exploitation of women. Later on, the scope of protection was enhanced by extending it to girls and adolescents and by eliminating the connotation of “white”. In parallel, other international agreements aimed to eliminate other forms of exploitation such as forced labor or child labor, were developed.
For the first time, the Convention for the Suppression of the Traffic in Persons and of Exploitation of the Prostitution of Others (1949) makes reference to “human trafficking”, although it does not define the concept and only stipulates sanctions for sexual exploitation.
It was not until the year 2000 when the international community reached an agreed definition of “human trafficking” which includes different forms of exploitation, such as labor, sexual, or removal of organs; and conceives that any person (woman, man, girl, boy or adolescent) could become a victim.
With the signing of the Protocol to Prevent, Suppress and Punish Trafficking in Persons, Especially Women and Children, Supplementing the United Nations Convention against Transnational Organized Crime, the international community adopts an instrument aimed to sanction different forms of exploitation while implementing preventive and protective measures for the victims of this scourge.