The US, Canada, and Mexico officially signed a new trilateral trade deal on Friday at the G20 summit in Buenos Aires. It’s known as the USMCA, or the United States-Mexico-Canada Agreement. (At least in the United States.)

While on the campaign trail, President Donald Trump had promised to renegotiate the North American Free Trade Agreement (NAFTA), which he called the “worst trade deal ever.” After more than a year of talks between the three countries, he’s finally made good on that promise.

Trump, Mexican President Enrique Peña Nieto, and Canadian Prime Minister Justin Trudeau celebrated the new deal on Friday, and Trump referred to it as a “groundbreaking agreement” during his brief remarks.

Trump also tweeted about the pact, calling it “one of the most important, and largest, Trade Deals in U.S. and World History.”