In the United States February 1 is National Freedom Day. Here are five facts you should know about the annual observance:

1. National Freedom memorates the date (February 1, 1865) when President Abraham Lincoln signed a joint resolution that proposed the 13th amendment to the United States Constitution. The amendment states that “Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction.” The 13th Amendment was ratified on December 18, 1865.

2. National Freedom Day was the idea of Major Richard Robert Wright Sr., a former slave who became a nationally renowned educator, journalist, and political figure. Wright was so well connected that he is reported to have known personally all the presidents from Rutherford B. Hayes (the 19thpresident) through Harry S. Truman (the 33rdpresident). He was almost ninety years old when he began to began to advocate for an memoration of what he designated “National Freedom Day.”

3. Wright formed the National Freedom Day Association in 1942. According to historian Mitch Kachun, Wright defined the purpose of the project in language that resonated with President Franklin D. Roosevelt’s Four Freedoms defining America’s goals for global peace: freedom of speech and worship and freedom from want and fear. The “adoption of National Freedom Day,” Wright said, was consistent with the principle articulated by President Roosevelt: “This principle implies that all men are not only equally entitled to all the freedoms, but some men in seeking to possess and enjoy these freedoms, must realize that they cannot have them without sharing them with others. In practice, they must prove that our declaration of freedom includes all men.”

4. Wright convinced several members of Congress to sponsor a National Freedom Day bill, which was introduced as a joint resolution of the House and Senate on January 19, 1942. At the age of 87, Wright traveled over 13,000 miles to rally support for the bill. Despite his efforts, the bill languished in Congress for five years before being defeated just a few weeks after Major Wright’s death in the summer of 1947. Wright was 92. One newspaper account reported that the major’s “last distinguishable words” as he lay on his deathbed were “National Freedom Day.”

5. The next year the bill was reintroduced and passed both houses of Congress without opposition. President Harry S. Truman—who was a cosponsor of the bill when he was in Congress—signed it into law on June 30, 1948. In 2010, President Obama designated the month of January as National Slavery and Human Trafficking Prevention Month, culminating in the annual celebration of National Freedom Day on February 1.