For the next four years, 2011-2015, the United States will commemorate the 150th anniversary of the Civil War, the most politically divisive — as well as the bloodiest — war in American history. 

The war eradicated the idea that one segment of the country could break away from the Union, abolished slavery and recognized the approximately 4 million newly freed black slaves as citizens with full civil rights (although it would take the civil rights movement of the 1950s and 1960s to finally fulfill that promise). The cost was more than 600,000 American lives. 

Of the 31.4 million inhabitants of the United States in 1860, approximately 3.1 million were Catholic, the overwhelming majority of them Irish and German immigrants, most of whom lived in the North. With very few exceptions, Catholics in the South supported the Confederacy and Catholics in the North supported the Union. Confederate President Jefferson Davis sent Bishop Patrick Lynch of Charleston, S.C., to Europe to persuade the governments of England and France to ally themselves with the Confederacy; the bishop also went to Rome to ask Blessed Pope Pius IX to recognize the Confederacy. Bishop Lynch’s mission failed, in large part because of the South’s intransigence on the subject of slavery. 

The Irish Brigade 

At the outset of the war, it was not certain if Irish Catholic immigrants would fight for the Union. The vast majority of Irish immigrants were refugees from the Potato Famine. Almost all of them were penniless, had no education, and had known no other life than tenant farming. In America they crowded into squalid slums, and took the backbreaking jobs native-born Americans didn’t want. Economically, the unskilled Irish were at the bottom of the pay scale, but they feared that if the war liberated the slaves, the market would be flooded with millions of African-Americans who would do the same work as the Irish, but for lower wages. 

The question was settled shortly after the opening shots were fired on Fort Sumter, when two of the most admired Irishmen in America called upon their fellow Celts to fight for the Union. Col. Michael Corcoran commanded the all-Irish 69th New York Infantry. In fall 1860, Queen Victoria’s eldest son, Edward, Prince of Wales (the future King Edward VII), came to New York. The city organized a number of special entertainments, including a grand military parade. When Corcoran’s superior officer ordered him to lead his men in the parade, he sent a note that read, “I could not in good conscience order out a regiment composed of Irish-born citizens to parade in honor of a sovereign under whose reign Ireland was made a desert and her sons forced into exile.” His stand made him a hero among the Irish. 

Also in New York at the time was Thomas Francis Meagher, an Irish patriot who in 1848 had led a failed attempt to overthrow the English government in Ireland, for which he was exiled for life to Australia. Meagher escaped to America, where the Irish welcomed him as a celebrity. When President Abraham Lincoln called for 75,000 volunteers to defend the Union, Meagher imagined an all-Irish Brigade that would prove their loyalty and courage to Americans who looked on Irish Catholics with contempt.  

The opportunity to fight with fellow Irishmen struck a deep chord among the Irish: In a matter of weeks almost 3,000 men were accepted for the Irish Brigade, which fought in every major battle of the Eastern theater. They lost so many men that twice Corcoran and Meagher were obliged to recruit new volunteers; by the end of the war, the Irish Brigade suffered 4,000 casualties, believed to be the highest casualty rate of any Union brigade.

The nun and the general 

Catholics were not found only among the rank and file. Gen. Pierre G.T. Beauregard of Louisiana was in command of the assault on Fort Sumter and was the victor of the first major battle of the war at First Bull Run. As captain of the CSS Alabama, Adm. Raphael Semmes destroyed or captured a record-setting 87 Union ships. And two of the South’s most successful spies, Belle Boyd and Rose O’Neal Greenhow, were Catholics. 

With his cavalry, Gen. Philip Sheridan rampaged through Virginia’s Shenandoah Valley, smashing every force the Confederates sent to stop him. William Tecumseh Sherman had been baptized a Catholic, but he had never been especially devout. In 1865, the conqueror of Atlanta and Savannah, Ga., entered Columbia, S.C., where he assured the superiors of the Sisters of Charity and the Ursulines that their property would not be harmed. Without his permission, Union troops looted and set fire to the city; the Ursuline convent and an asylum operated by the Sisters of Charity were destroyed. The next day, Mother Baptista summoned Sherman and gave him a dressing down. 

In fact, Catholic nuns played an invaluable part in the Civil War. Between 1861 and 1865, 500 sisters representing at least 20 religious orders from the North and South nursed wounded and sick soldiers. In 1862, Sister Angela Heath and four sisters from the Daughters of Charity motherhouse in Emmitsburg, Md., traveled to a field hospital in Manassas, Va. They found filthy shacks that passed as hospital wards, and 500 neglected patients. The nuns went to work at once, cleaning the shacks, washing the bedding, cooking nutritious food for their patients. Thanks to the sisters, the death toll in the hospital declined while the conversion rate increased: Sister Angela estimated that four out of 10 soldiers they nursed became Catholic. In 1924, the selflessness and heroism of all the nursing sisters was honored with a monument erected across the street from St. Matthew’s Cathedral in Washington, D.C. 

Catholic conspirators 

Sadly, two Catholics were implicated in the plot to assassinate Abraham Lincoln. Dr. Samuel Mudd, a Maryland physician, treated John Wilkes Booth’s broken leg the night the actor fatally shot the president. Historians still debate the degree of Mudd’s involvement in the plot, but in 1865 Mudd was sentenced to life in prison in the Dry Tortugas, islands off the coast of Florida. When a yellow-fever epidemic swept through the prison, he risked his own life to treat the guards and fellow prisoners. For his heroism, President Andrew Johnson released Mudd in 1869. 

Booth and his fellow conspirators met often at the home of Mary Surratt in Washington, D.C. She was a convert to Catholicism who raised her children in the Catholic faith. Her youngest child, John, intended to be a priest. When the war began, he left the seminary and became a Confederate secret agent. The night of the Lincoln assassination, John Surratt was in Elmira, N.Y.; when he learned that Booth had killed Lincoln, he fled to Canada, then traveled to Rome where he enlisted in the Papal Zouaves, one of the military units that guarded the pope. By then Surratt’s mother had been arrested, convicted of conspiracy and hanged. 

In Rome, Surratt was recognized, arrested and sent back to Washington for trial before a civilian court. The result of the trial was a hung jury, and he was released in 1868.

After the war 

Dr. Mudd and the Surratts’ involvement in the Lincoln assassination led to a flare-up of the old charge that Catholics could not be trusted. But the paranoia faded quickly. 

Like virtually every other institution in the South, the Church suffered devastating losses of property. In the North, however, the war set off an industrial boom — even unskilled Catholic immigrants could find good-paying factory jobs, which enabled many families to move out of the slums. Furthermore, the courage of Catholic troops and the compassion of the nursing sisters went a long way to reducing the anti-Catholicism that had been virulent in the country before the war. Such prejudice did not disappear, but the actions of Catholics during the war aided in their assimilation into the mainstream. 

Thomas J. Craughwell is the author of the forthcoming “The Greatest Brigade: How the Irish Brigade Cleared the Way to Victory in the American Civil War” (Quayside, 2011).