The 1862 letter was short, but its meaning was clear—and devastating. “You are hereby ordered to leave the city of Paducah, Kentucky, within twenty-four hours,” it read.

Cesar Kaskel couldn’t believe it. He had emigrated to the United States after leaving Prussia, where he was discriminated against and financially ruined because he was Jewish. Now, the Union Army was telling him he was being expelled from his new home and his business for the same reason.

Kaskel was about to become one of the Jewish people ordered to leave towns in Kentucky, Mississippi and Tennessee during the Civil War. They were victims of General Orders No. 11, a discriminatory wartime declaration issued by General Ulysses S. Grant.

Grant's decree was “the most sweeping anti-Jewish regulation in all of American history,” historian and rabbi Bertram W. Korn noted in his book American Jewry and the Civil War.

Though the 1862 orders were aimed at cotton speculators, they gave all Jews—speculators or no—just 24 hours to leave their homes, businesses and lives behind. It was the culmination of a wave of anti-Semitism that swept through the United States in the year before the Civil War… and a decision that would haunt Grant for the rest of his life.

By 1860 there were an estimated 150,000 to 200,000 Jewish people in the United States, up from 15,000 in 1840. That dramatic rise was the result of poverty and discrimination in Germany and Central Europe, where Jewish people were often excluded from trade, prevented from marrying and subject to pogroms and other violence.

The United States offered the promise of economic and social freedom. But Jewish immigrants were not always welcomed into their new communities, especially in the North. New Jewish enclaves in American cities were viewed with suspicion by those who recognized neither their language nor their religion. Once the Civil War broke out, things got even worse.

In the North, popular newspapers disparaged Jews as secessionists and rebels and blamed them for destroying the national credit. And though some Jews occupied high-ranking roles within the Confederacy, anti-Semitism was widespread in the South as well.

Almost as soon as the war began, illegal trade and smuggling between North and South started. Though the Union blockaded Southern ports, goods still made their way over the border, and profiteers continued their trade illicitly, especially as the price of cotton rose due to the embargo. Not only did illicit trading flout Union rules, but it threatened the war effort itself.

“When cotton came from Confederate territory,” writes historian Ludwell H. Johnson, “there was always the danger that it would be paid for in supplies or munitions.” The black market was everywhere, and it frustrated both governments. And there was a seemingly perfect scapegoat: Jews, who had been stereotyped in the press as avaricious and opportunistic.

General Ulysses S. Grant, one of the Union Army’s most influential officials, was infuriated by the cotton smuggling that damaged the Union’s ability to squeeze the South economically. In his eyes, the perpetrators were all Jews. This wasn’t borne out by evidence—though Jewish people were active as peddlers, merchants and traders, and some undoubtedly made money speculating on cotton, they did not make up the bulk of the black marketeers.

In August 1862, as Grant was preparing the Union Army to take Vicksburg, he commanded his men to examine the baggage of all speculators, giving “special attention” to Jews. In November, he told his subordinates to refuse to let Jews receive permits to travel south of Jackson, Mississippi or travel southward on the railroad.

For Grant, prejudice against Jews mingled with personal animosity. He began his crackdown after discovering a Jewish family’s involvement in a scheme to help use his father’s name to get a legal cotton trading permit in Cincinnati.

On December 17, 1862, Grant went even further. That’s when he issued an official order expelling Jews from the Department of the Tennessee, a massive administrative division under his command that included parts of Kentucky, Mississippi and Tennessee. He called the Jews “a class violating every regulation of trade established by the Treasury Department and also department orders” and gave them 24 hours to get out.

The order targeted Jews as a group, singling them out based on their religion. And though news of the order was hindered by Confederate raids and was not well-enforced, it slowly trickled out to Jews in and beyond the affected area.

News of the order horrified Jewish Americans. Among them were the approximately 30 Jewish merchants of Paducah, all of whom who were expelled from the city along with their wives and children. Two of the men being banished were former Union soldiers.

As they prepared to leave their homes and board a river boat away from Paducah, Cesar Kaskel and others telegraphed President Abraham Lincoln in a desperate attempt to spread the word about Grant’s actions. After their forced departure Kaskel went to Washington to protest the order in person. There, he approached Congressman John A. Gurley of Ohio, who agreed to accompany him to the White House. The men hurried to Lincoln.

But though an increasing number of people were learning of Grant’s orders in the South, the breakdown in communications meant that Lincoln had not previously heard about his general's decision to expel Jewish people from the Department of the Tennessee. He was so shocked by the order that he asked his staff for confirmation. Once they confirmed that it was real, he revoked it.

News of the order continued to spread, and though some editorials sided with Grant, most condemned its targeting of Jews. “Men cannot be condemned and punished as a class, without gross violence to our free institutions,” wrote the New York Times a month after the order. But even that editorial spread anti-Semitic tropes about Jews, comparing them to Shylocks and complaining about the potentially destructive power of wealthy Jews. Grant’s order helped stir up an ugly undertone of American life that isolated and damaged Jews who had come to the United States in search of an elusive equality.

The discriminatory order was quickly squelched, but the general never forgot it. In fact, he spent a lifetime trying to atone for it. When he was running for president in 1868, he confessed that the order “was issued and sent without any reflection and without thinking.” In office, he named more Jews to public office than ever before, and promoted the human rights of Jewish people abroad, protesting pogroms in Romania and sending a Jewish diplomat to object.

“During his administration,” writes historian Jonathan D. Sarna, “Jews moved from outsider to insider status in the United States, and from weakness to strength.” But though Grant did what he could to atone for his discriminatory order, he doubtless contributed to the anti-Semitism of the 19th century.