A group of students at UC Merced shook their heads on Wednesday afternoon when David Hayes-Bautista asked them if they knew why Cinco de Mayo is widely celebrated in America.

The UCLA professor of medicine and author of "El Cinco de Mayo: An American Tradition," then asked students if they knew what happens on Cinco de Mayo in Mexico.

"Nothing," one student in the audience responded.

The well-known holiday in this country is only celebrated in Puebla, Mexico. It's only a 45-minute celebration with a parade and a few speeches, Hayes-Bautista said. Why is that?

That's a question that Hayes-Bautista addressed at UC Merced as part of his tour of college campuses in California and other states. He's discussing his book and educating students about new information on the origins of the holiday.

Cinco de Mayo is not a Mexican holiday, said Hayes-Bautista, who spent several years researching the topic.

Hayes-Bautista told the students the holiday was created by Latinos living in California in 1862, and immigrants from Mexico and Latin America who had come to the state. They supported freedom and democracy after the Battle of Puebla, when Mexicans defeated the French.

That victory energized Latinos, and they decided to create a public day during the dark period of the American Civil War, he said.

Some of those instrumental in creating the holiday and spreading the word about it were members of 'Juntas Patrioticas Mexicanas' -- Mexican patriotic meetings. These gatherings took place in 129 locations, including 122 in California.

Some of the participants lived in locales such as Hornitos, Visalia, Stockton and Sonora. A few of their descendants are still in the area, Hayes-Bautista said. "You have a very, very rich history here," he told the students.

Hayes-Bautista said he wants students to know about the information he compiled about the holiday, details he didn't know about five years ago when he began his research.

Manuel Martin-Rodriguez, a literature professor at UC Merced, said Hayes-Bautista's visit was part of the Chicano Literature Speaker Series, which he started in 2005 when the school first opened its doors. Hayes-Bautista is the 31st speaker.

Martin-Rodriguez said he felt that the university needed to provide something other than instruction. By bringing speakers, it gives students and community members other perspectives on issues, he said.

The series is also important because the university has had a healthy Latino enrollment since it opened, and now it's considered a Hispanic-serving institution in the UC system, he said. "The need was even greater," he said of UC Merced.

Reporter Yesenia Amaro can be reached at (209) 385-2482 or yamaro@mercedsunstar.com.