Did you know that St. Patrick’s Day is celebrated in Mexico too? But not for the same reasons. They celebrate it because of the “San Patricios.”  The Saint Patrick’s Battalion (Spanish: Batallón de San Patricio) 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 or defected from the U.S. Army. Made up primarily of ethnic Irish and German Catholic immigrants, the battalion 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 the offer of generous land grants.

Members of the Battalion are known to have deserted from 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 US horse artillery.

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 these men 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. Others were conscripted on their way south by Gen. Zachary Taylor, with promises of salaries and land after the war.

Numerous theories have been proposed as to their motives for desertion, including cultural alienation, mistreatment of immigrant conscripts by nativist soldiers and senior officers, their not being allowed to attend Sunday Mass or to practice their religion freely, the incentive of higher wages and land grants starting at 320 acres (1.3 km2) offered by Mexico, and their witnessing poor conduct of U.S. troops following battle victories.

Some historians believed 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 Riley, and the field entries of senior officers.

So there you go.  Never mind green beer and four leaf clovers.  Today is a day to remember the brave men who fought to save Mexico from the invading U.S. forces.  God bless the San Patricios!