The 1926 Slavery Convention, an initiative of the League of Nations, was a turning point in banning global slavery. Article 4 of the Universal Declaration of Human Rights, adopted in 1948 by the UN General Assembly, explicitly banned slavery. The United Nations 1956 Supplementary Convention on the Abolition of Slavery was convened to outlaw and ban slavery worldwide, including child slavery. In December 1966, the UN General Assembly adopted the International Covenant on Civil and Political Rights, which was developed from the Universal Declaration of Human Rights. Article 4 of this international treaty bans slavery. The treaty came into force in March 1976 after it had been ratified by 35 nations.