Reconstruction of The Saint Patrick's Battalion's flag as described by John Riley.
Between 1845 and 1852 The Great Famine killed 1 million people and caused another million to flee the starvation and poverty they faced Ireland.
Many of these refugees went to the United States only to be handed a gun and a uniform the moment they stepped off the boat and told that they had a duty to help their new country and fight in the war against Mexico.
Thousands of conscripted Irish and European soldiers deserted the army on the march across Texas but one Irishman named John Riley refused to do so after becoming morally conflicted upon the realization he had become apart of the same type of conquering army that oppressed his people back in Ireland. Instead deciding to convince 200 other soldiers to defect with him and join the Mexican Army.
This group was composed primarily Irish immigrants but also included other Europeans from 8 countries and even escaped slaves from the Southern United States. They called themselves The Saint Patrick's Battalion.
During the battle of Monterrey The Battalion pushed back 3 separate assaults by US soldiers to take the town. This victory caused many more soldiers, even ones they fought against during the previous assault to defect from the US army and join their ranks. By some estimates up to 500 new soldiers enlisted in The Saint Patrick's Battalion.
In the Battle of Buena Vista an enraged U.S. Commander Zachary Taylor ordered a Cavalry Regiment to charge on the Battalion and take their position. This failed and the Cavalry Regiment was forced to retreat after heavy casualties. After the battle, General Francisco Mejia described the Battalion as “worthy of the most consummate praise because the men fought with daring bravery.” Several Irishmen were awarded the War Cross by the Mexican government for their conduct in Buena Vista, and many received field promotions.
With the hopes of causing more US soldiers to rethink the morality of their situation the Mexican government began producing desertion handbills which said:
"You must not fight against a religious people, nor should you be seen in the ranks of those who proclaim slavery of mankind as a constitutive principle. Liberty is not on the part of those who desire to be lords of the world, robbing properties and territories which do not belong to them and shedding so much blood in order to accomplish their views."
The Battalion continued to fight with distinction in several battles against US soldiers.
Pushing back the enemy in Matamoros after John Riley discovered the U.S soldiers had been raping the nuns.
At the Battle of Cerro Gordo when the Mexican troops realized they were out matched and broke rank to run the Saint Patrick’s Battalion stayed and fought the U.S. troops in hand-to-hand combat.
During the Battle of Churubusco while hopelessly outnumbered and under-equipped, the Mexican army 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 Saint Patrick's Battalion tore the white flag down, and proclaimed the men to fight on, with their bare hands if necessary.
After the Battle of Churubusco 50 captured Battalion members were hanged for treason in what was the largest mass execution in United States History.
It is said that while negotiating the end of the war the Mexican President was told that the U.S would not accept a peace treaty unless his government gave all members of the Saint Patrick's Battalion over to US custody so they could be executed for treason. The Mexican President purportedly responded that if he gave them a single soldier the war would never end because the citizens of Mexico would be so outraged he betrayed those heroes that they would hang him and then pick up rifles to carry on the Battalion’s mission.
After the end of the war the remaining members of the Battalion immigrated into Mexican life, many of them starting families and remaining in Mexico for the rest of their lives, with their descendants still residing in the hillsides of Mexico to this day.
After the war the U.S. Army denied the existence of the Saint Patrick's battalion as an attempt to discourage other deserters. It wasn’t until 1915 after Congress ordered the army to turn over its records on the battalion that the U.S Army admitted it ever existed.