Skip to main content

The San Patricios

June 2024
23min read

Most of them were American soldiers who fought with skill, discipline, and high courage against a U.S. Army that numbered Ulysses Grant in its ranks. The year was 1847.

The court-martial of Capt. John O’Reilly was one of twenty-nine convened by the United States Army at the San Angel prison camp in Mexico on August 28, 1847: thirty-six other men of O’Reilly’s San Patricio Battalion faced courts-martial on that same day at nearby Tacubaya.

The trials were swift. The prosecution established that each of the accused men had deserted from U.S. forces and then had fought against them in the captain’s Mexican outfit. Almost every man tried at San Angel and Tacubaya was convicted and sentenced to be hanged.

“These sentences, which would have been appropriate at any time, were particularly so now,” wrote Raphael Semmes, a Navy lieutenant who had served as a volunteer with the U.S. Marines in Mexico. “There were many foreigners in our ranks … and the enemy was making every effort still to entice them away. The salvation of the army might depend upon an example being made of these dishonored and dishonorable men.”

Semmes was a devout Roman Catholic, and like others of his faith serving in the U.S. forces, he believed that the men of the San Patricio Battalion had done a great disservice to American Catholics. Semmes recalled that “the brave Irish, who remained faithful to us … were more rejoiced at the event [of the convictions] than the native-born Americans even, as they felt keenly the stigma which this conduct of their countrymen had cast upon them.”

The U.S. soldiers reserved much of their anger for the mysterious John O’Reilly, whom they regarded as the archtraitor. He was the man who had led the others astray and had been seen in the middle of the fiercest fighting from Monterrey to Churubusco. It had been proved at his court-martial that he was formerly Pvt. John Reilly of K Company, 5th U.S. Infantry, and that he had deserted from General Taylor’s army when it reached the Rio Grande in April 1846. O’Reilly offered little in the way of a defense, but that little was artful: He considered himself a Mexican national, but he had been born in Ireland. “He expects to be hung,” wrote the U.S. medical officer at San Angel, “but denies the justice of it, as he calls himself a British subject.’

If the incident at Santa Isabel could outrage the young Lincoln, perhaps it convinced John O’Reilly that he was on the wrong side of a war.

O’Reilly’s Mexican nationality was endorsed by no less a sponsor than Santa Anna, who was then negotiating with President Folk’s envoy to end the war. He wanted the survivors of the San Patricio Battalion to be guaranteed prisoner-of-war status. The prisoner’s emphasis on his Irish birth had an effect as well. The British position on nationality in 1847 was “Once a Briton, always a Briton,” and there was no such thing as naturalization. Charles Bankhead, Britain’s minister to Mexico, visited the headquarters of Gen. Winfield Scott and volunteered to serve as an intermediary in a prisoner exchange. Bankhead was followed to Scott’s headquarters by the archbishop of Mexico City. Everyone was seeking the exchange, outright release, or ransom of the captain.

Scott was polite and gentlemanly to all his distinguished visitors, but he made his position clear. It was his duty to review the courts-martial and either approve or disapprove the sen- tences, and he assured the dignitaries that he would assess the captain’s case with the same attention to evidence as the others.

These visits were nevertheless an extraordinary intervention on behalf of a convicted Army deserter, but then “Brave Reilli” was a great war hero south of the border. A Mexican historian described him as “ un soldado de fortuna, aventurera de las armas, hombre gentil y apuesto, de gran simpática y fácil palabra, inquieta y temerario .” (He was “a soldier of fortune, a master of arms, a gentle, well-groomed, wellspoken, restless man of action who had great sympathy for Mexico.”)

Little is known about O’Reilly’s past (even the spelling of his name varies from Riley to Reilly to O’Rily ) beyond the fact that he was born in County Galway and was generally reported to have been a British army sergeant who deserted shortly after his regiment arrived in Canada in 1843. At the time of the trial he became the object of increasingly fabulous speculation—he had been a brilliant instructor of cadets at West Point, he was deeply involved with a propertied Mexican lady—but all the stories were promulgated to explain the inexplicable. John O’Reilly had to be more than a mere renegade private because he had confounded the U.S. Army for eighteen months.

The United States annexed Texas in December of 1845, and Gen. Zachary Taylor’s armv moved into the new state from Louisiana. When Taylor’s forces were ordered south of the Rio Nueces, every soldier knew what it meant. “We were sent here to provoke a fight,” wrote one officer. As Taylor advanced on the Rio Grande, the Mexican general Mariano Arista, hoping to avoid a clash with the U.S. troops before he could ascertain his orders, drew his patrols back to Matamoros. By moving south of the Rio Grande, he left the settlement of Santa Isabel to the Yankees.

When Taylor’s van entered Santa Isabel on March 25, 1846, part of the town and most of the outlying fields were in flames. The farmers and then the townspeople had panicked at the approach of the norteamericanos , and those with the means had fled across the river to Matamores. Those left behind were in terror, screaming, crying, expecting to be butchered by soldiers who, speaking no Spanish, were helpless to calm them. “All were Mexicans,” recalled a U.S. officer, “acknowledging none but Mexican laws. Yet we … drove those poor people away from their farms, and seized their custom-house at Point Isabel.” Several weeks later an antiwar congressman from Illinois named Lincoln asked his colleagues in the House what indeed they had expected to happen when Santa Isabel was occupied: “It is a fact that the United States Army in marching to the Rio Grande marched into a peaceful Mexican settlement, and frightened the inhabitants away from their homes and growing crops. … Possibly you consider these acts too small for notice. Would you venture to so consider them had they been committed by any nation on earth against the humblest of our people?”

If the incident at Santa Isabel affected a U.S. officer and stirred the eloquence of Abraham Lincoln, Mexican historians think it might have convinced John O’Reilly that he was on the wrong side of a war. One suggests that the flame and fear the private saw in Santa Isabel reminded him of the tales told in Ireland by those who had lived through the horrors of the Rising of 1798. Whatever his motivation, O’Reilly deserted.

For some reason, it took two weeks for him to be posted as a deserter. By that time the private was in Matamoros, and so were thirty other acknowledged U.S. deserters. General Taylor was not particularly concerned; he described the absent men as “old offenders,” most of them gone off to Matamoros for the liquor and women. They’d be back. But as more and more soldiers slipped across the Rio Grande in the darkness, Taylor was forced to order his pickets to “shoot to kill” any man who refused to return to Texas on a sentry’s command.

On April 4, some of the deserters did return. Under the cover of night John O’Reilly and a few Irish- men, wearing their old U.S. uniforms, ranged through the camp, dropping off leaflets that called upon all of Taylor’s European-born soldiers to recognize the U.S. presence on the Rio Grande as an aggression upon which “the civilized nations of Europe look with the utmost indignation.” The leaflets were signed by Gen. Pedro de Ampudia.

Three weeks later O’Reilly and his men were back, this time delivering leaflets addressed to the Irish, Germans, French, and Poles in the U.S. Army. Any one of them who chose to go to Mexico would receive full citizenship and a land grant of at least 320 acres. The acreage increased in proportion to rank and experience; a first sergeant, for instance, would receive 500 acres plus an additional 100 acres for each year of service. This leaflet was signed by Don Mariano Arista, Ampudia’s commander.

Arista, impressed by the daring and coolness with which O’Reilly had led these two nocturnal sorties, commissioned him a lieutenant in the Mexican Army and authorized him to raise a company of volunteers from among the expatriates in Matamoros. Mexican sources state that O’Reilly quickly recruited forty Irishmen and four esclavos negros —slaves brought along with Taylor’s army as grooms and valets to Southern-born officers. In Georgia or Alabama freedom was a long and treacherous run northward; in Texas it was a river away, and these blacks were free men and soldados de Mexico now. As for the others, not all were Irish. Thomas Millet, Hezekiah Akles, John Hartley, Alexander McKee, and John Bowers were among the early recruits, and these five men may have been responsible for the direction the company was going to take. All were deserters from Battery H, 3d U.S. Artillery. Field guns were one arm of the service in which even a junior lieutenant could exercise independent command. O’Reilly determined that his would be an artillery company.

The expatriates were in training when Arista learned that Mexico had declared war against “ La Injusta Invasión Norteamericana .” Mexican lancers engaged and defeated U.S. cavalry north of the Rio Grande, but Taylor lost little time in defeating Arista at PaIo Alto and Resaca de la Palma. In both these battles U.S. “flying artillery” units distinguished themselves, dashing about the field and starting fights, rather than wait for the fights to find the guns.

Arista’s chief artillerist, on the other hand, managed to get himself captured, and no one seemed to have had any idea what to do with the guns once he was gone. The still obscure Lieutenant O’Reilly’s company, which had seen no action as yet, pulled back with the rest of Arista’s forces to Monterrey, leaving Taylor’s army to wait out the broiling summer months in Matamores.

A great deal of antiwar literature was turning up in Matamoros, and much of it was directed at the consciences of abolitionists. Papers and religious tracts told soldiers that this was not only an unjust war but an insidious plot to spread slavery westward. In twos and threes, in squads, and in sections, about fifty men deserted, and they marched to Monterrey to put on the black shakos, the dark blue red-trimmed uniform coats, the white cross belts, and the sky blue trousers of O’Reilly’s outfit. Some of these men were motivated by religion and some by sympathy; others were adventurers drawn by the lure of land; but all were present under arms as Mexican soldiers that grim September when Taylor moved against Monterrey.

During the fighting General Ampudia often hurried to the hottest action, and inevitably he found O’Reilly and his gunners there before him. “Valientes como leones,” (“valiant as lions”) reported the general. Ampudia recommended that O’Reilly be entrusted with two brass cannon on top of the Bishop’s Palace stairs during the evening of the second day’s fighting. The Obispado was not expected to hold; U.S. troops would hit it from three sides at dawn. Positioned there were tough Mexican regulars, men who had no illusions about why O’Reilly’s men were carrying kegs of powder into the palace.

The norteamericanos attacked at first light, and they were hurled back by the regulars and the point-blank fire of O’Reilly’s guns. The Yankees came on again, and again were driven back. Throughout the fighting two Irish pioneers with lit torches waited close by fuses. The moment the position was overrun, they would send the Obispado , defenders, and attackers up in one huge, annihilating blast of black powder.

But after repelling a third assault, the forces at the palace were ordered to fall back on the plaza. They retired in good order, the sporadic skirmishing gradually dying down to leave an eerie silence over the streets of Monterrey. Taylor and Arista had worked out a cease-fire.

It lasted six weeks, time enough to give Don Antonio López de Santa Anna, the canny Mexican politician and soldier who, a decade after massacring the garrison of the Alamo, had managed to make himself known as the “Angel of Peace,” an opportunity to negotiate a peace with the United States. Taylor’s army would occupy Monterrey; Arista’s would march south with all honors of war. U.S. soldiers watched the long column depart, the veteran troops in the van, the rear made up of wives, children, camp followers, and even pets. Taylor’s men enjoyed the withdrawal as much as a circus parade until the officer commanding the rear, a magnificently mounted lieutenant, came into view. The U.S. soldiers recognized John O’Reilly; they shouted threats and curses, and, according to an officer, “the dastard’s cheek blanched.”

O’Reilly’s outfit did not stay long in bivouac. With other crack units of Arista’s army, it marched south to San Luis Potosí, where a very formidable force was mustering to be commanded by Santa Anna. Far from negotiating an end to the war, the Angel of Peace had decided to throw the norteamericanos out of Mexico.

Between 150 and 200 men were integrated into O’Reilly’s unit at San Luis. The nucleus of the force remained the U.S. deserters and occasionally a reluctant draftee.

Among the new recruits were some Irish frontiersmen from Texas who considered themselves Mexicans rather than Texans or Americans. They called their settlement San Patricio, or St. Patrick, and they may have given the name of their home to the battalion that was taking shape at San Luis.

However the outfit gained the name, it was a fitting one. More than a third of the force and all but three of the officers were Irishmen, and the unit fought under a green battle guidon that bore an image of St. Patrick. After some lobbying, O’Reilly acquired five heavy cannon, eighteen- and twentyfour-pounders. Their crews trained under Lt. Ned McHerron, formerly a sergeant of G Battery, 4th U.S. Artillery, and, as his ex-commander said, “a loyal and faithful soldier for many years in the United States Army.” A deeply religious man in his sixties, McHerron had been appalled by reports of U.S. soldiers desecrating churches at Matamoros. He made the march to Monterrey with a few comrades; one who refused to accompany him was another sergeant, his son.

McHerron became the mainstay of an uncommonly effective “flying artillery” battery. Cannon had to be protected in the field, and as late as the Civil War this could be a confusing, haphazard business of generals improvising support by taking men from battle lines and assault columns. But the support systems were built into the San Patricio Battalion from the start: outriders, two infantry companies, and sharpshooters made up of soldiers who knew their only job was to get the guns into action, maintain them, and withdraw them safely.

The San Patricios liked to sing “Green Grow the Lilacs”; it is said that the Mexican soldiers began to refer to their comrades as los greengros .

In early February a group of U.S. prisoners spotted swift-moving caissons, support troops double-timing behind the guns, and one of the captives was disgusted to see the guidon bearer “bearing aloft in high disgrace the holy banner of St. Patrick.” The San Patricios were on their way to Buena Vista, where on February 23, 1847, they fought Capt. John Paul Jones O’Brien’s D Battery, 4th U.S. Artillery. After breaking up a charge of the 1st U.S. Dragoons, O’Reilly then turned his fire on O’Brien. Within minutes the San Patricio “heavies” had silenced the U.S. six-pounders with fire so fast and accurate that it killed all of O’Brien’s horses and left most of his men dead or wounded. The captain had to abandon his last two intact pieces; some of O’Reilly’s outriders dragged them back to the Mexican lines.

But from this point the battle deteriorated steadily for the Mexicans. Santa Anna ordered an abrupt withdrawal, which turned into a rout late that afternoon, and Taylor hoped to smash him by nightfall. “But one Mexican battery continued its fire on our troops,” wrote the war correspondent John Bonner. “This was the 18- and 24-pounder battery of the Battalion of San Patricio, composed of Irishmen, deserters from our ranks, and commanded by an Irishman named Riley.”

Los soldados de San Patricio had helped open the battle, and now they were closing it. Two U.S. flying batteries under Capt. George Davis and Capt. Braxton Bragg skirmished cautiously with the better-armed San Patricios, but as night fell, Bonner reported, “the San Patricio Battery still commanded the southern edge of the plateau.”

The San Patricio Battalion lost twenty-two men in this stubborn, skillful rearguard action, and O’Reilly was promoted to captain. By late March he had a price on his head—U.S. authorities wanted him dead or alive- and the battalion was ordered south into action against Gen. Winfield Scott’s army, which had taken Veracruz and was driving overland toward Mexico City.

Every Mexican village and town the San Patricios marched through cheered them on their way to face Scott. Many of the men were redheaded, ruddy, and badly sunburned, and the Mexicans nicknamed them the Red Ones or los Colorados . A song that sprang up along the route was carried around the world as a sea chantey during the gold rush a few years later: “Santy Anna gained the day/Aweigh, Santy Anno / Zach’ry Taylor ran away / All on the plains of Mexico.” Another song and story are connected with the San Patricios: At day’s end they would sit around their campfires singing a song called “Green Grow the Lilacs.” The story goes that the Mexican sol- diers began to refer to their comrades as los greengros .

On April 18,1847, Los Gringos fought an impressive holding action in the mountains at Cerro Gordo. They were now heroes to the Mexicans, but they had suffered heavy casualties by this time, particularly among the new men. The professionals among them knew that Mexico was going to lose the war and that, as one of them wrote, “we fight with the halter around our necks.” On July 7, 1847, the officers of the San Patricios presented a document to their major, Francisco Moreno, a contract between the Mexican Army and “we, the undersigned foreigners of the Foreign Legion Companies of St. Patrick.”

It was a simple, straightforward paragraph that assured the San Patricios of their lands and bounties or relocation to a neutral country after the war. The document bore overtones that “Brave Reilli” had shown his true colors—as a mercenario —but he did have a responsibility to his men. Generals he trusted approved the contract, but it remained to be seen how many San Patricios would live to collect on its terms.

Quite a few of them died in the rugged fighting at Contreras on August 20. Throughout the day the U.S. forces made repeated charges against the Mexican positions, carried them at last, and recovered the two cannon O’Brien had lost at Buena Vista. In the lastditch fighting over those guns, eleven San Patricios were taken prisoner.

Scott determined to push on at dawn. He knew Santa Anna’s army was virtually destroyed, strung out from the battlefield clear to Mexico City in an agonized retreat that was converging on a bottleneck at the bridge over the Río Churubusco. Yet some generals were calling out to units of this beaten army as they trudged by, and those units joined the sweat-streaked men who were sandbagging positions on the bridge for a last stand. In all, some fifteen hundred regulars and national guardsmen stood ready to fight a delaying action. The San Patricios had their guns emplaced at the bridgehead, camouflaged with cornstalks; their cannoneers would fight beside two other companies, the Bravos and Independencias , while the rest drew off to a secondary position, the Convento de San Pablo. The convent, now a thicket of stockades and chevaux-de-frise, resembled another holy place not so very long before turned into a fortress by desperate men. Its defenders were all that stood between Scott and Mexico City. They waited in the convent, in the trenches, and at the bridgehead.

By midmorning the Mexican generals could taste victory and begged Santa Anna to send up reinforcements. But few came.

Advance U.S. scouts under Gen. William Worth saw nothing but the debris of a shattered army at the Rio Churubusco next day. General Scott had sent a division under Gen. David E. Twiggs along a northern causeway at dawn, expecting to flush out and flank any rear guard at the Churubusco. Twiggs was moving along grandly, skirmishing now and then with Mexican cavalry, and still, nothing was stirring at the Churubusco.

When given the order to advance, General Worth hurled his division forward. He was determined to beat Twiggs to the gates of Mexico City, and, with no cavalry screen or skirmish line, his three brigades walked right into the trap. The Mexicans opened fire at point-blank range, smashing two brigades and sending the third scrambling for cover in the cornfields. The murderous crossfire from the bridgehead and the convent beat back wave after wave of U.S. attacks.

By midmorning the Mexican generals could taste victory, and they begged Santa Anna for reinforcements and ammunition. But few reinforcements came, and most of the ammunition sent back was useless. Furious Mexican soldiers at the Río Churubusco, men who would have gladly died for the republic, were not going to get themselves slaughtered for Santa Anna. Entire regiments shouldered empty muskets and marched toward Mexico City.

The U.S. Army was also in bad shape, but Scott noticed the slackening of the Mexican fire, and at his command troops under Franklin Pierce and the Irish-born James Shields flanked the battalions at the bridgehead.

These Mexican troops retreated on the convent, but not all of them obeyed the order to withdraw. As the victors approached the abandoned gun emplacements, the U.S. soldiers could see the San Patricio bodies sprawled in their trenches and lying across their cannon. Then, on McHerron’s command, the dead sprang to life, fired one last volley from their heavies, and about sixty of them came screaming out of the smoke with swords, bayonets, and clubbed muskets. Young Lt. Ulysses Grant recalled it as “the severest battle fought in the valley of Mexico…the gunners who had stood their ground were deserters from Gen- eral Taylor’s Army on the Rio Grande.” Among the few San Patricios who survived the action was a wounded Ned McHerron.

The fighting now shifted to the stockade in front of the convent, where O’Reilly and his men put up a stiff resistance until U.S. troopers materialized before them. It happened that these cavalrymen were actually Mexicans of the U.S. Spy Company. When this outfit had been recruited at the Puebla jail, the U.S. authorities believed the men to be political prisoners. In fact they were common criminals commanded by a convicted murderer and bandit named Manuel Domi’nguez, now a brevet colonel. But they had rendered yeoman service to Scott, operating behind the Mexican lines, and they were the first U.S. troops to breach the walls of the convent.

For a few desperate minutes the San Patricios fought among the rearing horses and hacking sabers, trying to plug the breach. But U.S. infantrymen now were scaling the walls, dropping into the courtyard, and joining the melee.

At last the Mexican forces were forced back into the convent, where they piled debris into makeshift barriers, while overhead their marksmen blazed away at the men attempting to ram through the doors. When two draftees attempted to show a white flag, a San Patricio sergeant knocked them senseless. Then the entire convent shook as a direct hit from a U.S. cannon carried away part of the upper floor. The Mexican commanders, deciding that any further resistance was pointless, had the cease-fire sounded.

Capt. James Smith was the first U.S. soldier into the smoky alcove where hundreds of Mexican troops had been penned up with the surviving San Patricios. A Mexican colonel there determined to make a fight of it if the San Patricios were attacked, and this seemed a real possibility because, as one U.S. soldier wrote, “every deserter would have been bayoneted or shot dead on the spot.” Smith had his hands full trying to prevent an atrocity, and O’Reilly did not help matters by refusing to surrender to a mere captain. A colonel was produced, but even he was not good enough for the Irishman. And the situation remained explosive until General Twiggs himself entered the convent and accepted John O’Reilly’s sword. Capt. George Davis of Scott’s staff thought that the capture of the San Patricios “proved a greater source of gratification to our entire army than any other single event of that memorable day’s victories.”

A head count revealed eightyfive San Patricios at the convent. Eleven others had been captured the day before at Contreras. About ninety-six were accounted for out of a battalion once perhaps three hundred strong. Although captured, the San Patricios were not quite defeated. An officer, apparently Patrick Dalton, informed a U.S. colonel that if the men were treated as prisoners of war, “we will not take up arms against the United States again .” The threat was only implied, but it was enough of a threat to cause the U.S. authorities to split up the men of the battalion.

It is interesting that George Pickett, who fought for one lost cause, raised the flag that meant death for men who had fought gallantly for another.

As the prisoners waited under guard at San Angel and Tacubaya, another attempt was made to negotiate an end to the conflict. The war correspondent George Kendall, who denounced the San Patricios as “a precious set of scoundrels,” voiced a general concern when he wrote that if peace came too early, “the rascals might get off easily.”

But the rascals were not going to get off easily; sixty-five men were tried and condemned by U.S. courts-martial. In reviewing the cases, however, Scott found that the courts had been overzealous. Two naturalized Mexican citizens, an Irishman and an Englishman, had offered important testimony that was disregarded. Exonerated were John Brooke and Henry Never, who, as stretcher-bearers, had risked their lives many times to save wounded U.S. soldiers. Lewis Preifer was pardoned because he was mentally deficient, and Davey McElroy was freed because he was only fifteen years old.

A surprise pardon was given to the San Patricio lieutenant Ned McHerron, who had earned the respect and interest of Captain Davis. There was a strange extenuating circumstance in McHerron’s case: His soldier son had displayed such gallantry on the U.S. side that he was now a brevet lieutenant. Davis recalled that “the deserter condemned to death was unconditionally pardoned, and the only reason assigned by General Scott for this unexpected clemency was…‘In the hour of the greatest temptation, his son was loyal and true to his colors.’”

Some of the death sentences were modified because of technicalities. Millet, Akles, Hartley, McKee, and Bowers had deserted before the war and thus could not be executed under the U.S. Articles of War. And on that same argument John O’Reilly could not be executed either. Scott gave him the stiffest punishment allowable for desertion in peacetime: fifty lashes and a branding with the letter D for “deserter,” the brand to be set “high up on the cheekbone, near the eye, but without jeopardizing the sight.”

Captain Davis wrote of “intense dissatisfaction and an urgent remonstrance among the officers of the army” at this finding. Some officers declared that they would rather see all the other San Patricios spared than have John O’Reilly escape the hangman on such a base and obscure point. Scott retorted that he had reviewed the cases as honestly as he could, and before he did an injustice to any man, he would “rather with his whole army be put to the sword!”

In General Order No. 281 Scott left fifty death sentences standing, and on the night of September 9 sixteen San Patricios at San Angel prison camp were told they would die the next morning.

At dawn on September 10, eight transport wagons drew up under a specially built gallows. Two San Patricios stood in each wagon. Among them was the young captain Patrick Dalton. At the trials he had been repeatedly identified as O’Reilly’s second-in-command, but he was apparently the battalion’s adjutant. He was the only San Patricio officer to draw a death sentence, because he had deserted after war was declared. A drum sounded, the wagons rolled out from under the men’s feet, and fifteen “died without a struggle,” a witness reported. The exception was Dalton: By accident or design, his noose had been loosened, and he spent a long time strangling.

O‘Reilly and the others sentenced to be flogged were tied to trees in front of the Church of San Angel. Two mule drivers with bullwhips took turns laying the fifty lashes on O’Reilly’s bare back. His flesh, said one observer, soon had “the appearance of a pounded piece of raw beef, the blood oozing from every stripe as given.” O’Reilly suffered through his flogging in grim silence, but he screamed and passed out when branded on the right cheek. An officer inspected the damage and noticed the brand had been applied upside down. The captain was brought back to consciousness, and the brand was reapplied correctly.

As the mule drivers moved on to the next man, a U.S. officer found the entire scene “revolting,” and a reporter described it as “the most cruel and sanguinary scene that was probably ever enacted in a war.” Captain Davis wondered what kept these men alive: “it was a marvel to me.” Some were fitted with eight-pound iron collars; they were to be confined at hard labor and dishonorably discharged when the U.S. Army left Mexico. The U.S. surgeon at San Angel had to treat the men after their punishment. “They were lured from their duty by the magnificent promises of Santa Anna,” he wrote, “bore the brunt of his battles, were poorly paid, and finished their career in damning ignominy.” The next day, September 11, four San Patricios were hanged at Mixcoac.

Mexico did not forget O’Reilly. After the war a San Patricios monument was raised; in 1960 a commemorative medal was struck.

Mexico was outraged by what its papers termed “barbarities” inflicted on men “who had carried themselves with the highest courage.” But the outcry over the San Patricios was eclipsed by the renewal of the war. Charging Santa Anna with violating the truce, Scott sent his army down Molina del Key to attack Mexico City. The key to the city’s defense was the fortress at Chapultepec, and as the U.S. soldiers prepared to attack it on September 13, 1847, thirty San Patricios were brought to Mixcoac to be hanged. All of them were bound at chest, hands, and knees, and the nooses set in place. Then they waited, watching the white fortress of Chapultepec Castle two miles away.

Col. William S. Harney, commanding the execution detail, pointed his sword toward the fortress and told the condemned that at the very moment the Mexican flag was replaced by the Stars and Stripes—“the flag you have dishonored”—they would die. For hours they waited in the shadow of death under the broiling sun. One soldier in the detail thought it “a gross refinement of cruelty such as we might expect to find among the Indian tribes.… The soldiers were unanimous in their expression of abhorrence and detestation at the diabolical inhumanity of the proceeding.”

But Colonel Harney was in command. Clouds of gunsmoke hid the flag as the U.S. troops battled their way into the fortress. Section after section had to be taken, often in handto-hand combat, and in one of those sections a wounded Captain Murphy was captured. The U.S. soldiers decided that he was a San Patricio, and Murphy, sword in hand, was about to die gamely when a senior Mexican officer intervened, pointing out that Murphy was the son of Mexico’s minister to Britain. The U.S. soldiers apologized and pressed on with the battle.

And in the end, the lives of the San Patricios at Mixcoac rested in the hands of an eiehteen-vear-old cadet named Augustín Melgar. Mexico’s West Point was housed in the fortress at Chapultepec, and Santa Anna had ordered “the boys” out before the battle. But the boys, los niños , voted to stay and fight, and their courage was epitomized by Melgar, who made his stand under his flag. Ammunition gone, he fought with his bayonet until he died.

The U.S. platoon that took Melgar’s position was commanded by a West Pointer named George Pickett, and he carried an American flag in his tunic. In the next war, Lieutenant Pickett and one-quarter of the U.S. Army’s officer corps would switch sides to fight for another flag. Even Raphael Semmes, who found the San Patricios “dishonored and dishonorable men,” would follow his conscience and serve against the Stars and Stripes. So it is interesting that Pickett, whose famous charge was the high-water mark of one lost cause, raised the flag that meant death for men who had fought gallantly for another. Pickett ran up his flag: and when the guards at Chapultepec saw it, they started to cheer. “As soon as the flag was seen floating in the breeze they were launched into eternity,” an artillery man remembered. “What must have been the feelings of those men when they saw that flag—for they knew their time had come! But on the other hand, a cheer came from them which made the valley ring.”

John O’Reilly and the surviving San Patricios were imprisoned at hard labor in the Citadel. A few more San Patricios turned up, but now that the war was over, the United States had little interest in them. However, the Mexican Army did have, and the Foreign Legion companies remained on the rolls. Captain McHerron wanted to retire to his Mexican lands, and the vacancy was filled in October 1847. The new commander of the San Patricio Battalion was a distinguished U.S. officer, Michael O’Sullivan, who resigned his commission to rematerialize as a full colonel in the Mexican Army a week later.

To the dismay of many U.S. officers, men were requesting permission to join O’Sullivan’s outfit. Others were interested in starting ranches or businesses in Mexico and wanted to be mustered out of the Army there. There would be trouble, possibly even a mass desertion, if these men were forced to return to the States just to be discharged. Of all people, Colonel Harney went to Washington to represent their position to the President, and he got honorable discharges for every U.S. veteran who preferred to remain in Mexico. The U.S. Army withdrew from Mexico City on June 1, 1848, and moving in right behind the departing troops as guards at the presidential palace and the legations were O’Sullivan’s men.


One of the last duties of the U.S. forces in Mexico City involved a punishment detail. John O’Reilly and his men, heads shaved, were driven from the Citadel by fife and drum rattling out “The Rogue’s March.” Beyond the gates of the Citadel, the guards watched astonished as O’Reilly took off his tattered prison garb and drew on the most magnificent tunic any of the soldiers had ever seen. It was the formal uniform coat of a Mexican colonel, emblazoned with the orders and decorations awarded to a foreigner by a grateful nation. After mounting a fine horse, Don John spurred off in the company of Mexican generals.

It turned out to be bad company. O’Reilly became involved in an aborted military coup at a time when Mexico was tired of dictators, and he was exiled. He probably left to return to Ireland in 1850, but there the trail gives out. There’s no record that he ever got home.

If O’Reilly was not forgotten in Mexico, neither were his men. The people of San Angel raised a monument to the San Patricios after the war. It was a cross bearing three images: a gamecock, a pair of dice, and a skull and crossbones. The imagery was summed up best by the historian Edward S. Wallace in 1950: “These unfortunate men were brave and fought, gambled, and lost.”

In 1960 a commemorative medallion was struck in honor of the San Patricios—“ con la gratitud de Mexico a los 113 años de su sacrificio” “—with the thanks of Mexico on the 113th anniversary of their deaths.” On its face are the escuda national , Mexico’s eagle and serpent, and an Irish cross. Unlike the grim symbols of the cross of San Angel, this one is decorated with sea horses and wolfhounds, and it is inscribed “Al Heróico Batallón de San Patricia—1847.”

On the reverse “un soldado irlandes con la vista fuera” (“a grim-faced Irish soldier”)leads his men to the stock ades at the Río Churubusco. In the background are a heavy cannon and the walls of the Convento de San Pablo.

There are no words inscribed on that side of the coin. In Mexico no words are necessary.

Enjoy our work? Help us keep going.

Now in its 75th year, American Heritage relies on contributions from readers like you to survive. You can support this magazine of trusted historical writing and the volunteers that sustain it by donating today.