This is what some men do when their country tells them they are not wanted.

When the United States entered World War 1 in April 1917, many African-American men decided to enlist. But when they tried to sign up in the regular army, they were segregated into a separate unit, the 369th Infantry Regiment, and sent to Camp Whitman, New York. Here they learned basic military procedures. After that, they were sent to Spartanburg, South Carolina for combat training. When they arrived in the south, they endured extreme racism and were refused service at the local stores. The 369th suffered through all these indignities, trained diligently, and finally, two days after Christmas, 1917, they embarked for Europe.

When they got there, they found that they were unwanted; white soldiers in the American and British armies refused to fight alongside black men. The 369th was shunted off to non-combat labor duties. But soon after, the French – who were more open minded and in dire need of reinforcements – offered to take them in. An arrangement was made, and the 369th was packed off to join the French army’s 16th Division. They were given French helmets, rifles, and pouches, but kept their American uniforms.

They called themselves the Black Rattlers; the French called them the Men of Bronze. But it was the enemy who would give them their enduring nickname. When the 369th finally reached the front and started fighting, the Germans quickly learned to fear the soldiers they called the Harlem Hellfighters.

They made an immediate impact. In one of their earliest battles, in April 1918, two Harlem Hellfighters named William Henry Johnson and Needham Roberts took on a 24-man German patrol, until they ran out of ammunition and fought on, armed only with the butts of their rifles and a bolo knife. In July and August, in the Second Battle of the Marne, the Harlem Hellfighters turned back a German offensive and triggered a devastating allied counterattack. In September, they surged forward into the Argonne Forest, advanced 14 kilometers through heavy fire, and captured the important village of Sechault. In November, as the final German defenses were collapsing, the Harlem Hellfighters were the first American soldiers to reach the Rhine. Germany surrendered on November 11.

Of all the units that served in World War 1, the Harlem Hellfighters served the longest tour – six months of continual service. Through that period they suffered over 1500 casualties but never lost one foot of ground, never had a man taken prisoner, and achieved every single battle objective save one.

The French certainly appreciated them. The Harlem Hellfighters received over 100 individual honors from the French government. Private Johnson was the first American to win the Croix de Guerre, for extraordinary valor. And the regiment received a unit Croix de Guerre with Silver Star, for the taking of Sechault.

One hundred years ago this month, they returned to the United States; the first New York unit to return to their home city. And when they arrived, oh man what a welcome! Thousands of New Yorkers lined the streets as the Harlem Hellfighters, led by their own regimental jazz band, proudly marched from Washington Square Park, up Fifth Avenue and into the heart of Harlem.

It was a defining moment for racial justice that reverberated for decades.

And it was a hard-earned victory, won by one of the greatest fighting forces in American history.