On Sept. 12, 1997, Mexican President Ernesto Zedillo held a ceremony in Mexico City in honor of the 150th anniversary of the San Patricio Battalion. Representing Ireland, Ambassador Sean O’Huighinn was also present at the ceremony. Although at least two historical accounts have been written about the Mexican Irish soldiers, for the most part, the general population of the United States is not aware of the Irish who fought for Mexico during the Mexican-American War. Few, outside of Mexico, have ever heard of the Irish soldiers who defected from the American lines and bravely fought defending Mexico from the American invasion. This is the story of the Batallón de San Patricio, a group of Irishmen fighting for Mexico. For Mexicans, the men of the San Patricio Battalion will forever be enshrined in Mexico’s hall of honor.

The Mexican-American War lasted for two years, from 1846 until 1848. It resulted in 25,000 Mexican soldiers dead or wounded. Mexico also lost about 40 percent of its territory. The Americans suffered 17,423 dead or wounded and had over 9,000 soldiers go AWOL, according to American records. The war started as a result of the declaration of independence by the State of Texas in 1836 and the subsequent annexation of Texas into The United States in 1846. On May 11, 1846, U.S. President James K. Polk asked and received approval by Congress to declare war on Mexico.

As America prepared for war, thousands of European immigrants hit the American shores. Among these were the Irish who were fleeing the Great Hunger of 1845. With the offer of free acres of land and three months of advanced pay, many enlisted in the American army.

John Miller, in his book; “Shamrock and Sword” writes that the desertion rate for American forces was the highest during this conflict as compared to other wars. According to Miller, the rate was 8.3 percent, compared to 5.3 percent for World War II and 4.1% for the Vietnam War. Peter Stevens, in his book; “The Rogue’s March: The Saint Patrick’s Battalion” wrote that no U.S. Army has ever encountered the problems of desertion that plagued Generals Zachary Taylor and Winfred Scott. He adds that of nearly 40,000 regulars, 5,331 deserted.

Very few historians have written about the San Patricios. There are two reasons for this, on the American side the war was unpopular and was ultimately over shadowed by the American Civil War. Besides the debate within the United States about the war, the high desertion rates from the American lines made the discussion of the war taboo within the American military. On the Mexican side, the loss of a substantial part of its territory and the ongoing civil strife within Mexico has left a lack of historical record for the war.

Historians on both sides of the border have generally acknowledged that the Americans were intent on instigating war with Mexico through unprovoked crimes; such as rapes and plunder and especially the desecration of Catholic Churches in Texas, the disputed territory. Also, many immigrants in the American army not only felt discriminated upon by their fellow soldiers but also could not accept the American provocation for war. They began to desert and cross the river to join the Mexican army in defense of Mexico.

German Christopher Friedrich Wilhelm Zeh wrote in his memoirs that the U.S. Army was a multicultural group where one of every thousand was an immigrant. Although the American Army was composed of recent immigrants, discrimination permeated through the ranks. Catholic prejudice and harsh treatment by superiors and the use of extreme disciplinary measures such as flogging added to the reasons for the desertions from Taylor’s ranks. “Potato heads” as the Irish were commonly called were particularly singled out for harsh treatment. Under these conditions the immigrants had no difficulty abandoning their army and joining the Mexican lines in defense of Mexico. Mexico was especially active in recruiting the deserters.

Mexico has historically recruited foreigners to fight in its ranks since its war of Independence.

Throughout the war, Mexico actively recruited American soldiers to defect their lines and join the Mexican army. The German immigrant Zeh, serving in the US Army acknowledges in his memoirs that the Mexicans routinely passed out pamphlets directed at the American immigrant soldiers printed in German, English and French. According to Zeh, the pamphlets read; “We live in peace and friendship with nations you come from. Why do you want to fight against us? Come to us! We will welcome you as friends with open arms, take care of your needs, we offer you more than the Yankees can provide, due to their brazenness, we (sic) have been forced into this war. Join us and fight with us for our rights and for our sacred religion against this infidel enemy.” Zeh adds, “Several hundred Irishmen, stirred up by religious fanaticism, went over to the enemy, thanks to this piece of paper.”

In October of 1846, after an additional 50 or so American soldiers had deserted the American ranks, bringing the total number of deserters to about 100, Santa Anna, using war powers bestowed upon him by the Mexican Congress, directed that two infantry companies be formed. The two companies would form the Batallón de San Patricio. According to a dissertation by author Dennis Wynn, the battalion was formed in October of 1846 as a separate unit. Additionally, according to Mexican army payroll records for November 1846, “Voluntarios Irlandeses” were receiving pay from the Mexican government for that period. Although the San Patricio Battalion was made up predominantly of Irish immigrants, other European nationalities also comprised the element. Of the 175 members of the San Patricio Battalion, 40 were from Ireland, 22 from the United States, 14 from the German States and the rest from other countries.

John Riley of K Company, 5th Infantry deserted his American post and joined the Mexican ranks on April 12, 1846 prior to the U.S. declaring war on Mexico. Part of the confusion over whether Riley organized the battalion is caused by the different spellings of his name found in official government records. John Riley, himself signed his name as Riley, other times as Riely, Reilly, or O’Riley in his correspondence to others. Mexican government records list him as Juan Reyle, Reley, Reely or Reily. His enlistment record for the U.S. Army lists him as Reilly.

On Sept. 2, 1845, Riley enlisted for a five-year term at Fort Mackinac. He left for the Texas border two days later. During the last three weeks in March of 1846, Riley, under Taylor’s Army, setup camp in Texas, just across the river from Matamoros. On April 12, 1846, Riley obtained a pass from Captain Merrill to attend a Catholic Mass, deserted and joined the Mexican Army. According to the records of the period, Sergeant John Riley’s ability was such that he was in line for a lieutenant’s commission although rising through the ranks during this period was difficult at best. By most general accounts, The San Patricios fought bravely throughout the war. The Battle of Buena Vista and Churubusco is where the battalion left its most notable war marks.

One of the most “vicious” battles of the war was the Battle of Buena Vista fought on Feb. 22 and 23 of 1847, near Saltillo. In this battle 4,759 Americans engaged about 15,000 Mexicans. Rather than a battle, it was a series of fights with few positions changing hands; consequently it was at first difficult to tell who had won. General Francisco Mejia’s Buena Vista Battle Report lauded the San Patricios’ “as worthy of the most consummate praise because the men fought with daring bravery.”

On Aug. 19 and 20 of 1847, Mexico suffered two devastating defeats, the second of which saw the destruction of the San Patricios as a unit in this war. Of the original 120 San Patricios, 35 were killed in action and 85 were captured by American forces.

After the battle, the captured San Patricios were tried for desertion during war time and all were found guilty and sentenced to death by hanging. Under General Scott’s, General Orders 281 and 283, issued in the second week of September 1847, Scott upheld the capital punishment for 50 of the soldiers, pardoned five and reduced the sentences for the other fifteen. John Riley was included in the last fifteen because he had deserted during peace time and therefore could not receive the death penalty. Riley had deserted prior to the official declaration of war.

Under orders of Winfield Scott, the last of the 50 San Patricios were hanged facing Chapultepec Castle precisely at the time the American flag was raised after the American victory during that battle. The mass executions left a deep impression on the Mexican population. Rioting broke out in Toluca after the news reported that the executions had taken place. Mexicans intent on seeking revenge threatened to kill American prisoners but were prevented from doing so by the Mexican authorities. From the Mexican point of view, the San Patricios should have been treated as prisoners of war, not criminals.

Instead of hanging, Scott ordered that the 15 San Patricios spared the death penalty, be instead branded with a two inch letter “D” for desertion with hot-iron on the right cheek and receive 50 lashes. Scott also ordered that the San Patricios be imprisoned until the American army left Mexico. Upon being mustered out, Scott ordered that the men’s heads be shaved and drummed out of the Army. Although Scott intended to return the San Patricio men back to the United States at the conclusion of the war, the Mexican government prevailed in keeping them in Mexico.

The Mexican Government had called the punishments an act of barbarism, “improper in a civilized age.” Under the terms of the Treaty of Guadalupe Hidalgo, the San Patricio prisoners were to be left in Mexico. Mexico had insisted on this clause in the treaty during the negotiations. Maj. Gen. Butler issued General Orders 116 on June 1, 1848. In the last paragraph of that order, Butler ordered that; “The prisoners confined at the Citadel, known as the San Patricio prisoners, will be immediately discharged.” After the officer in charge of the Citadel read the orders, the 16 prisoners, including John Riley had their heads shaved, the buttons of their uniforms stripped off and marched out of the fortress while the bugler played “Rogue’s March.” John Riley, instead of being branded once, was branded twice according to some of the reports of the time. The reports indicate that the double branding may have been a result of the first “D” being applied backwards, either intentionally or under orders. The second “D” was then applied correctly.

It can be argued that the defense of your homeland is a duty all citizens must obey when an invading army threatens to destroy your country. Many heroes have emerged from the defense of their nations. No truer hero exists than those who give their lives for their adopted nation.

Part of the reason for the lack of more concrete information regarding the San Patricios and the distortion of their reasons for deserting the American army may lie in that the whole affair was an embarrassment to the United States. Continued Catholic persecution in the United States after the war may have also contributed to the distorted record. “Some newspapers in San Francisco cite that affair to prove that Catholics are disloyal,” wrote a private citizen in a letter to the Assistant Adjutant General in 1896 requesting information on the San Patricios. Because of sentiments against Catholicism and the harsh treatment by American forces of the San Patricios, the American Army seemed reluctant to discuss the affair publically. In 1915, the American War Department was finally forced to acknowledge the existence of the San Patricios and their treatment of them at the end of the war. Ordered by Congress in 1917 to turn over the records to the National Archives the army complied. The documents detailed one of the most embarrassing episodes for the American Army. For the San Patricios, their story could finally be told truthfully for all to know what was true in their hearts.

After leaving prison, the remaining San Patricios rejoined the Mexican Army and continued to function as a unit for almost a year after the Americans left Mexico. Riley was made commander of the two infantry companies with the brevet rank of Lieutenant Colonel, although he was actually a Captain. One unit was tasked with sentry duty in Mexico City while the other was stationed in the suburbs of Guadalupe Hidalgo. By late 1850, 20 of the original San Patricios left Mexico and returned to Ireland under the agreement Mexico had made with them when they enlisted to help them return should they choose to do so. Riley was not among them.

John Riley died on the last days of August 1850 and was buried in Veracruz under the name “Juan Reley”, the name under which he had enrolled into the Mexican Army.

Mexicans celebrate the Irish soldiers on two days, Sept. 12 in honor of the anniversary of the first executions and on March 17, St. Patrick’s Day. Numerous street names across the country honor their contribution to the Mexican cause. In front of the Convent of Santa María in Churubusco the street is named “Mártires Irlandeses”, or Irish Martyrs.

The Mexican government has officially recognized the contribution of the San Patricios through official acts of government. In 1997, President Zedillo held a ceremony in honor of the 150th anniversary of their executions along with Ireland’s ambassador. On Thursday, Oct. 28, 2002 the LVII Mexican Congress held a ceremony where the inscription “Defensores de la Patria 1846-1848 y Batallón de San Patricio” or “Defenders of the Fatherland 1846-1848 and the San Patricio Battalion” was inscribed in gold letters on the Wall of Honor in the Chambers of the Congress. Three hundred and ninety-four Mexican congressmen, along with Irish Ambassador to Mexico, Art Agnew, attended the ceremony recognizing the sacrifices made by the young Irish soldiers.