The celebration of Cinco de Mayo began as a form of resistance to the effects of the Mexican-American War, which occurred in the late 19th century. The holiday gained popularity during the Chicano Movement of the 1960s and 1970s. By the 1980s, companies began commercializing the holiday.

Here’s a quick breakdown of the history of Cinco de Mayo, when it is and why it’s celebrated more in the U.S. than it is in its country of origin.