The Slavery Convention is signed

On September 25, 1926, the first signatures went onto an international treaty with a plain and ambitious aim: to suppress the slave trade and slavery. Its formal name was the Convention to Suppress the Slave Trade and Slavery, and it was drafted under the League of Nations, the international organization founded in 1920. It took effect on March 9, 1927, the same day it was registered in the League’s treaty series.

The treaty built on earlier agreements. The Brussels Conference Act of 1890 had targeted the traffic in African slaves, and the Convention of Saint-Germain-en-Laye of 1919 committed the victorious Allied powers to work for the complete suppression of slavery. Yet slavery persisted. When the League asked governments about it in December 1923, every one of them replied that slavery did not exist in their territory or had already been abolished. An informal inquiry in 1922 and 1923 had already pointed to chattel slavery in the Arabian Peninsula, Sudan, and Tanganyika, and to forced labor in several colonies, so the League decided a formal investigation was needed.

In 1924 the League set up the Temporary Slavery Commission, a panel of eight experts that included the former colonial governor Frederick Lugard and the Haitian representative Dantès Bellegarde. Its investigation and its 1925 report laid the groundwork for the convention.

Why it matters

The convention gave the world a legal definition of slavery: “the status or condition of a person over whom any or all of the powers attaching to the right of ownership are exercised.” It also defined the slave trade broadly, covering every act of capturing, buying, selling, or transporting a person to reduce them to slavery. Signatories agreed to prevent the trade, to bring about the end of slavery in all its forms progressively, and to impose severe penalties.

The treaty outlived the League itself. A protocol that entered into force in 1955 amended it, and in 1956 the United Nations extended it with the Supplementary Convention on the Abolition of Slavery. By 2013, 99 countries had committed to the convention in some form, and its definition still shapes how international law describes slavery and human exploitation.

Did you know?

The convention did not create a permanent watchdog. The League later set up a Committee of Experts on Slavery to check how well the treaty was working, and that committee led to the first permanent body on the subject, the Advisory Committee of Experts on Slavery.