​St. Patrick’s Day is really popular in Mexico—and the reason why is surprising

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In the U.S., St. Patrick's Day is a number of things: young (and some not-so-young) people mark the day as an occasion to drink copious amounts of beer and whiskey; others celebrate the feast day by chowing down on corned beef and cabbage; others see the day as an opportunity to drive all the serpents from Ireland (maybe). Ultimately, the day is about the Irish and Irish pride. Arguably, though, the country that shows its Irish pride on St. Patrick's Day might be Mexico, where the day is celebrated as a sort-of military holiday, in honor of El Batallón de los San Patricios.

Saint Patrick's Battalion was a group of European immigrants and expatriates, overwhelmingly Irish, who had (mostly) defected from the United States army to fight alongside Mexico during the U.S.-Mexico War of 1846-48. Their reason for deserting is largely attributed to religion: the U.S., and its army, was majority Protestant, and the Catholic servicemen felt marginalized and reminded of their experience under Protestant British rule in Ireland, so they fled to Catholic confines of Mexico.


The war started after the U.S. tried and failed to buy territory from Mexico, including California and Nevada. However, before war was officially declared, John Riley, a "crack artilleryman" believed to have previously served as a British officer before coming to America and enlisting, and a group of fellow Irishmen joined Mexico's army. They immediately became an integral part of Mexico's defense and some of the army's most experienced cannoneers, participating in nearly every important battle in the war, their distinct green silk flag flying nearby. Many received field promotions and commendations for their bravery from the head of the army, and Mexican president, General Santa Anna.

Riley's believed to have designed the group's flag, an image of St. Patrick emblazoned over the Mexican coat of arms with the Gaelic phrase "Erin Go Bragh," a phrase denoting allegiance to Ireland, loosely translated as "Ireland Forever."

During the Battle of Churubusco, the San Patricios were surrounded and outnumbered, having retreated into a monastery. They repelled numerous assaults, but were devastated when a shell hit their gunpowder supply, destroying much of their weaponry. They launched a counter-assault with only their bayonets, even ripping down the surrender flag their Mexican brothers in arms had hung, but they were soon captured.


The San Patricios were court-martialed and hoping to avoid treason charges, claimed they were forced to desert by Mexico, or had too much to drink and didn't realize what they had done until it was too late. Those who were unsuccessful using that defense received very harsh punishments: 48 were sentenced to hang, and the ones who had deserted the U.S. army were whipped, branded, and sentenced to hard labor. Riley was eventually released by the U.S. army and returned to Mexico and served in the army before retiring in Veracruz.

After winning the war and signing a treaty, the U.S. took a large parcel of Mexican territory as its reward, according to Latino Rebels:

"More than two-thirds of the Mexican Territory was taken, and out of it the United States would carve California, Nevada, New Mexico, Arizona, Utah, Wyoming, and parts of Kansas and Colorado.

[the war] added more to the national treasury and to the land mass of the United States than all other wars combined."


The San Patricios are a well-known part of Mexican history, but little known elsewhere. There are plaques dedicated to Riley and his cadre, like this one:


There are streets named in honor of the San Patricios throughout Mexico, including in Monterrey and Mexico City. The San Patricios are part of the Wall of Honor in the Chamber of Deputies of Mexican Congress and the Mexican government even gifted the town of Clifden in Ireland, John Riley's hometown, with a statue of the man. Every year, in San Angel, near a plaque that lists the names of 71 of the San Patricios who died during "The Unjust North American Invasion," a commemoration is held. Mexican and Irish dignitaries attend, and other ceremonies are held, usually with bagpipes, keeping the ties between the two countries strong to this day.

So, if you're toasting St. Patrick today with a Guiness, maybe do a shot of tequila as well in honor of Riley and the San Patricios.


David Matthews operates the Wayback Machine on Fusion.net—hop on. Got a tip? Email him: david.matthews@fusion.net