Many Mexicans are aware of St. Patrick and some of the associated Irish customs and folklore, such as Leprechauns (called Duendes in Spanish).  St. Patrick’s Day is celebrated in both the United States and Mexico on March 17th.  However, in Mexico St. Patrick’s Day is not a day to celebrate all things Irish with drinking and partying as it is in the United States.  That is not to say that one cannot find St. Patrick’s Day celebrations in Mexico, especially in places with tourists and immigrants.  In Tijuana, for example, there have been years where the bars have served green beer on St. Patrick’s Day.St. Patrick’s Day is one of two days when Mexico honors the valiant service of The Saint Patrick’s Battalion (Batallón de San Patricio or los San Patricios), primarily Irish soldiers who had deserted from the U.S. army and fought in the Mexican army against the United States during the Mexican-American War of 1846-48.  The other day that Mexico honors los San Patricios is September 12th, the date when captured members of the Saint Patrick’s Battalion were executed for desertion from the U.S. Army. Mexican children born on March 17th are often named (the Spanish equivalent of) Patrick or Patricia in honor of St. Patrick.  And los San Patricios.In Mexico St. Patrick’s Day is a civic or cultural holiday; it is not a  federal statutory holiday.  Employees do not get a day off with pay.  Banks, schools, government offices, and businesses are open as usual.

The Saint Patrick’s Battalion (Batallón de San Patricio or los San Patricios), which was formed and led by Jon Riley, was a unit of 175 to several hundred immigrants (accounts vary) and expatriates of European descent who fought as part of the Mexican Army against the United States in the Mexican-American War of 1846 to 1848. Most of the battalion’s members had deserted from the U.S. Army.  Made up primarily of ethnic Irish and German Catholic immigrants, the battalion also included Canadians, English, French, Italians, Poles, Scots, Spaniards, Swiss, and native Mexicans, most of whom were Roman Catholics.  Disenfranchised Americans were in the ranks, including escaped slaves from the American South.  The Mexican government offered incentives to foreigners who would enlist in its army granting them citizenship, paying higher wages than the U.S. Army and they offered generous land grants.  Only a few members of the Saint Patrick’s Battalion were actual U.S. citizens.Members of the Battalion are known to have deserted from U.S. Army regiments including: the 1st Artillery, the 2nd Artillery, the 3rd Artillery, the 4th Artillery, the 2nd Dragoons, the 2nd Infantry, the 3rd Infantry, the 4th Infantry, the 5th Infantry, the 6th Infantry, the 7th Infantry and the 8th Infantry.The Battalion served as an artillery unit for much of the war.  Despite later being formally designated as infantry, it still retained artillery pieces throughout the conflict.  In many ways, the battalion acted as the sole Mexican counter-balance to U.S. horse artillery.  As an infantry unit, the San Patricios continued to serve with valor and great distinction.  Examples are given below.Knowing that they were likely to face the death penalty if captured, the San Patricios are known to have threatened wavering Mexican troops with death by “friendly fire” at the Battle of Cerro Gordo if they retreated.  When the San Patricios were too-heavily engaged to carry out their threat, the Mexican troops broke and ran, leaving the San Patricios as they fought U.S. troops in hand-to-hand combat.The Battle of Churubusco (August 20, 1847) took place two days after the defeat at Cerro Gordo.  General Santa Anna gave a verbal order to “preserve the point at all risk.”  The San Patricios initially met the attackers outside the walls of the convent at tête-de-pont, which was about 500 yards from a fortified convent.  A battery of three to five heavy cannons were used from this position to hold off the American advance along with support from Los Independencia Batallón and Los Bravos Batallón.  Several U.S. charges towards the bridgehead were thrown off, with the San Patricio companies serving as an example to the supporting battalions.  Unlike the San Patricios, most of whom were veterans (many having served in the armies of the United Kingdom and various German states), the supporting Mexican battalions were militia who were untested in battle.A lack of ammunition led the Mexican soldiers in the trenches between the bridgehead and the convent to disband; without ammunition, they had no way to fight back.  Santa Anna had ordered half of these soldiers to a different part of the battlefield.  When the requested ammunition wagon finally arrived, the 9½  drachma cartridges were compatible with none but the San Patricio Companies “Brown Bess” muskets, and they made up only a fraction of the defending forces.  Further hampering Mexican efforts, a stray spark from an artillery piece firing grape shot at the on-coming U.S. troops caused the just-arrived ammunition to explode and set fire to several men, including Captain O’Leary and General Anaya.  A withdrawal behind the walls of the Convento de Churubusco was called when the threat of being outflanked proved too great. The San Patricios used this battle as a chance to settle old scores with U.S. troops.  The large number of U.S. officers they killed in the affair is generally considered as revenge because they engaged in no similar acts during the war.  Though hopelessly outnumbered and underequipped, the defenders repelled the attacking U.S. forces with heavy losses until their ammunition ran out and a Mexican officer raised the white flag of surrender.  Officer Patrick Dalton of the San Patricios tore the white flag down, prompting General. Pedro Anaya to order his men to fight on, with their bare hands if necessary.  American Private Ballentine reported that when the Mexicans attempted to raise the white flag two more times, members of the San Patricios shot and killed them.  After brutal close-quarters fighting with bayonets and sabers through the halls and rooms inside the convent, U.S. Army Captain James M. Smith suggested a surrender after raising his white handkerchief. Following the U.S. victory, the Americans are said to have “ventilat[ed] their vocabulary of Saxon expletives, not very courteously, on Riley and his beautiful disciples of St. Patrick.”For Americans of the generation who fought the Mexican-American War, the San Patricios were considered traitors.  For Mexicans of that generation, and generations to come, the San Patricios were heroes who came to the aid of fellow Catholics in need.The great majority of San Patricios were recent immigrants who had arrived at northeastern U.S. ports; part of the Irish Diaspora’s escaping the Irish Potato Famine and extremely poor economic conditions in Ireland, then part of the United Kingdom of Great Britain and Ireland.  The U.S. Army often recruited Irishmen and other immigrants into military service shortly or sometimes immediately on arrival, with promises of salaries and land after the war.Some historians believe a primary motivation was shared religion with the Mexicans and sympathy for the Mexican cause, likely based on similarities between the situations in Mexico and Ireland.  This hypothesis is based on evidence of the number of Irish Catholics in the Battalion, the letters of Jon Riley, and the field entries of senior officers.  Another hypothesis is that the members of the Saint Patrick's Battalion had been unhappy with their treatment in the U.S. Army.  Another theory some historians hold is that the San Patricios were attracted by the valuable incentives offered by the Mexican government: higher wages and generous land grants.  For poor people coming from famine conditions, economics was often an important incentive.Mexican author José Raúl Conseco noted that many Irish lived in northern Texas, and were forced to move south due to regional insecurity.  Early in the war they helped U.S. General Zachary Taylor attack the fort and supply depot in St. Isabel, now the city of Port Isabel, Texas.Irish expatriates have a long tradition of serving in military forces of Catholic countries, for instance, serving with Spain in groups of young men known as the Flight of the Wild Geese in the 17th century.  In addition, many Irish fought as soldiers in South American wars of independence.The San Patricios captured by the U.S. Army were treated and punished as traitors for desertion in time of war. In addition, they had been responsible for some of the toughest fighting (and the heaviest casualties) that the U.S. Army faced.  Seventy-two men were immediately charged with desertion by the U.S. Army; military law required death as the punishment for the crime of desertion during a time of war.Those who survived the war generally disappeared from history.  A handful are on record as having made use of the land claims promised them by the Mexican government.The San Patricios have continued to be honored and revered as heroes in Mexico.  The Batallón de San Patricio is memorialized on two separate days; September 12th, the generally-accepted anniversary of the executions of those convicted by the U.S. Army of desertion at time of war, and March 17th, Saint Patrick's Day.Numerous schools, churches and other landmarks in Mexico take their name from the battalion, including:Monterrey:  The street in front of the Irish School is named Batallón de San Patricio Mexico City:  The street in front of the Santa María de Churubusco convent was named Mártires Irlandeses. The coastal town of San Patricio, Jalisco.The battalion’s name is written in gold letters in the chamber of Mexico's House of Representatives.In 1997, Mexican President Ernesto Zedillo commemorated the 150th anniversary of the execution of the San Patricios at a ceremony in Mexico City's San Jacinto Plaza.  This is where the U.S. Army conducted the first 16 hangings after the men were convicted of desertion. Ireland and Mexico jointly issued commemorative postage stamps to mark the anniversary.In 2004, at an official ceremony attended by numerous international dignitaries including directors Lance and Jason Hool, as well as several actors from the film One Man's Hero (1999), the Mexican government gave a commemorative statue to the Irish government in perpetual thanks for the bravery, honor, and sacrifice of the Saint Patrick’s Battalion.  The statue was erected in Clifden, Connemara, Ireland, where Jon Riley, the leader of the San Patricios, was born.The battalion has inspired numerous responses: it is the name of a soccer team club Deportivo Chivas USA’s supporters association, was evoked in a Saint Patrick’s Day message from Subcomandante Marcos of the Zapatista Army of National Liberation, and has been remembered as a symbol of international solidarity with Mexico.  In honor of Jon Riley, on September 12th the Irish town of Clifden, the birth place of Jon Riley, flies the Mexican flag.Traditionally most Irish Americans have distanced themselves from the San Patricios.  They have not wanted to be associated with deserters or thought to be disloyal.