By Emily Lefler

The 1st Infantry Division, known as the “Fighting First,” is celebrating its 102nd birthday on June 8. Originally commissioned in 1917 to fight in World War I, the unit is the oldest continuously serving division in the U.S. Army.

In honor of its birthday, here are seven facts you should know about the unit:

1. Why the “Fighting First”?

During World War I, the 1st Infantry Division set sail for Europe just six days after its commissioning. A few days later, when they landed in St. Nazaire, France, they became the first U.S. combat unit to fight on European soil, earning them the nickname the “Fighting First.”

Service Series poster promoting the First Division as a unit that works around the clock, showing half-length drawing of a soldier, holding rifle, on the face of a clock. | Photo credit Library of Congress

2. Speaking of nicknames

Another nickname for the 1st Infantry Division is the “Big Red One,” which refers to the unit’s signature patch. Just like it sounds, the patch, which is in the shape of a pentagram, has a distinctive large number one in the middle of it. There are two different stories about the exact origin of the patch design.

The first story claims that, during World War I, the unit’s supply trucks were painted with a large figure “1” on the side of each truck. This, in turn, prompted soldiers to start wearing the red number one on their sleeves.

The second story, which is arguably the more popular tale, claims that, during training, a general decided that the unit should have shoulder insignia and proceeded to cut a number “1” symbol from his red flannel underwear. A young lieutenant saw this and shouted, “the general’s underwear is showing,” prompting the general to challenge him to come up with something better, which he did. The young lieutenant’s design, which was an olive green or grey piece of fabric with a red number “1” symbol on it, became the first version of the unit’s modern-day patch.

3. A history of firsts

The 1st Infantry Division paved the way for many “firsts” throughout history. During World War II, the unit was the first to reach England, fight the enemy in North Africa and Sicily, reach beaches of Normandy on D-Day and capture a major German city, Aachen.

Photo credit NARA/Coast Guard Chief Petty Officer Robert F. Sargent

Troops of Company E, 16th Infantry, 1st Infantry Division (the Big Red One) wade onto the Fox Green section of Omaha Beach on the morning of June 6, 1944.

In 1965, the unit was the first division called to fight in Vietnam, battling the enemy for five years and carrying out aid programs to those in South Vietnam. During the Gulf War, as part of the VII Corps, the division was the first to lead the charge into Iraq, eventually cutting off the path of retreat for the Iraq Army along the Kuwait border.

In 2006, during the Iraq War, the division became one of the first units deployed in support of the Iraq Surge. As part of Operation Inherent Resolve, the Department of Defense identified the unit as the first division to deploy to Iraq, supporting the nation’s strategy to destroy ISIL and provide assistance to the Iraqi Security Forces.

4. Meet Rags, the unit mascot and a war hero

In 1918, Pvt. James Donovan, a member of the unit found a stray dog on the streets of Paris and named him Rags. Rags was immediately adopted by the 1st Infantry Division as a mascot and went with Donovan to the frontlines in World War I.

The Parisian pup proved to be a major asset for the unit during battle. In addition to carrying messages between advancing infantrymen and their supporting field artillery, Rags was also used as an early warning system for artillery shell fire. Because of his acute sense of hearing, Rags was able to detect incoming shells before the soldiers could hear them, saving several lives. While on the frontlines, Rags suffered injuries to his right paw, ear, and eye, and was gassed by German shells.

Photo credit U.S. Army Signal Corps

Rags with Sgt. George E. Hickman.

After the war, Rags traveled to the U.S. where he was honored with a number of medals and awards. Rags passed away in 1936 and buried with military honors. He even had a monument erected in his memory.

5. “The Big Red One” song

The 1st Infantry Division march, “The Big Red One” song, was composed by Capt. Donald T. Kellett during World War II. Kellett created the song while he was in the hospital recovering from wounds he suffered in Algeria during the Battle for Hill 609. The march was dedicated to Maj. Gen. Terry Allen, who awarded Kellett the Silver Star at Kasserine Pass, Tunisia.

Here are the lyrics:

Toast of the Army,

Favorite Son! Hail to the brave Big Red One!

Always the first to thirst for a fight.

No foe shall challenge our right to victory.

We take the field, a grand sight to see.

Pride of the Infantry.

Men of a great division,

Courage is our tradition,

Forward the Big Red One!

6. The 1st Infantry Division goes to Hollywood

The 1st Infantry Division was the focus of a feature film, aptly named “The Big Red One”, in 1980. Directed by Samuel Fuller, a World War II veteran that served in the 1st Infantry Division, the movie is centered on a sergeant and four members of his unit as they battle their way throughout Europe in World War II. The movie received very positive reviews. Empire magazine ranked it 483rd on their list of the 500 greatest movies of all time, and it was even entered into the 1980 Cannes Film Festival.

7. “Call of Duty 2: The Big Red One”

Did you know that the 1st Infantry Division is featured in the video game franchise “Call of Duty”?

In the game “Call of Duty 2: The Big Red One”, players take on the role as a soldier in the unit during World War II. The storyline follows the division’s efforts throughout the war, including the North Africa campaign, the invasion of Sicily, the landing on Omaha Beach and their movements east, including crossing the Siegfried Line into Germany.