According to the Huffington Post, many people celebrate Cinco de Mayo for the wrong reasons. The holiday is not Mexico's Independence Day, which is September 16, but rather celebrates the country's brief victory over French forces in 1862. Cinco de Mayo also relates to the mass immigration to California by people in Mexico and Central and South America during the Civil War and those people's fight for the abolition of slavery.
The Huffington Post reports:
David Hayes-Bautista, a professor of medicine and health services at UCLA and author of the newly released "El Cinco de Mayo: An American Tradition," said the holiday's history in the U.S. goes back to the Gold Rush when thousands of immigrants from Mexico, Central and South America came to California during the Civil War.
According to Spanish-language newspapers at the time, this first group of multinational Latinos on U.S. soil identified with the Union Army's fight against the Confederacy and often wrote pieces about the evils of slavery. Hayes-Bautista said these Latino immigrants were concerned about the Union's lack of progress and Napoleon III's interests in helping the South.
"It wasn't until the news came about the Battle of Puebla that they got the good news they wanted," said Hayes-Bautista. "Since Napoleon III was linked to the Confederacy, they saw the victory as the first sign that their side could win."
They didn't, of course, at least not for a few years. French forces took over Mexico after the Battle of Puebla, and installed Habsburg Archduke Maximilian as Emperor of Mexico. He was captured by Mexican forces five years later and put to death.
But in the years that followed, Latinos in California and the U.S. Northwest celebrated Cinco de Mayo with parades of people dressed in Civil War uniforms and gave speeches about the significance of the Battle of Puebla in the larger struggle for abolition, said Hayes-Bautista.
Read more at the Huffington Post.