US President Joe Biden signed the Juneteenth National Independence Day Act into law Thursday establishing June 19 as a US federal holiday that commemorates the end of slavery in the country.

The Senate unanimously passed the Juneteenth National Independence Day Act Tuesday without amendment. The Act then passed overwhelmingly in the House Wednesday with a 415-14 vote. After Biden signed the Act, Juneteenth became the eleventh US national holiday, and the first new national holiday since Martin Luther King Jr. Day was created nearly four decades ago.

Federal employers will observe Juneteenth 2021 for the first time on Friday, June 18, as June 19 falls on a Saturday.

The Act signing was livestreamed with an opening statement by Vice President Kamala Harris, who noted that Juneteenth has been known by many names throughout history: “Jubilee Day, Freedom Day, Liberation Day, Emancipation Day, and today, a national holiday.”

Biden followed and shared how over the course of decades, 94-year-old Opal Lee made it her mission to see that this day came. Those in attendance gave Opal Lee, the “grandmother of the movement to make Juneteenth a holiday,” a standing ovation. Biden thanked those who contributed and said, “I’ve only been president for several months, but I think this will go down for me as one of the greatest honors I will have had as President, not because I did it, you did it—Democrats and Republicans.”