John Charles “Jock” Campbell began his military career with the British Army’s Honourable Artillery Company during World War I. However, it was during World War II that he received his greatest renown. His leadership of an independent “flying column” of troops against Italian forces in 1940 was so effective that these formations became known as “Jock columns.”

Later, his decisive command and frontline heroism during Operation Crusader in 1941 earned him the Victoria Cross.

Brigadier General Hugh Elles was the first commanding officer of the British Army’s Tank Corps, which was formed from the Machine Gun Corps’ Heavy Branch in 1917. Determined to prove the value of tanks, Elles led plans for a massive assault on German forces near the French town of Cambrai that would require tanks, cavalry, and infantry to attack in tandem.

The Battle of Cambrai began on November 20, 1917, with Elles commanding from a tank near the formation’s center and flying a Tank Corps flag of his own creation. The combined forces ultimately broke through German defenses.

Leo Geyr von Schweppenburg began his military career with the German Army in 1904. He participated in both World War I and World War II, climbing the ranks as the years passed. From 1937 to 1939, he led the 3rd Panzer (armored) Division, which, with 391 tanks, was the largest division involved in the 1939 invasion of Poland.

Afterward, Geyr achieved success in eastern Europe, particularly during Heinz Guderian’s 1941 invasion of the Soviet Union, before being sent to France and becoming tasked with command of the newly formed Panzer Group West in 1943.

As the first director-general of the British Army’s Tank Corps, Major-General Sir John Edward Capper played a key role, along with Hugh Elles, in expanding the use of armored vehicles in war; in fact, Elles served as the corps’ operational commander beneath him.

Yet Capper enjoyed a career as a venerated military engineer well before that. In 1915, he was appointed Chief Engineer of the British Army; prior to that, in 1907, he and Samuel Franklin Cody achieved the first flight of a British military airship.

Ernest Swinton was not only a career officer in the British Army; he was also a military scholar, theorist, and engineer responsible for key elements of the general design of armored vehicles. Swinton’s inspiration came in a 1914 letter from friend Hugh Marriott, who suggested that tracked tractors could have not just agricultural but military uses. When development of the new armored vehicle stalled, in 1915, Swinton sent a statement of work to Commander-in-Chief John French.

Records suggest that in a meeting in December of that year, Swinton also coined the vehicle’s name: the military tank.

In 1917, under the leadership of General John Pershing, Lieutenant Colonel LeRoy Eltinge was assigned the task of determining what would be needed in order for the U.S. military to establish a tank corps or “Combat Tank Service” as part of its American Expeditionary Forces.

In addition to studying and recommending British and French tanks for military use, Eltinge made another particularly notable contribution to U.S. military history that year: he recommended that a then-Captain George S. Patton, Jr., apply to join this new tank service.

After the U.S. Tank Corps was formed in 1917, it was placed under the command of Brigadier General Samuel D. Rockenbach, a career military officer whose service extended back to the 1890s and the Spanish-American War. Rockenbach, reporting directly to General Pershing, was a dedicated advocate for the use of tanks in war; in 1918, he tasked his officers to write first-hand accounts of their experiences with operating tanks, to provide a better understanding of armored vehicle combat.

His advocacy continued after World War I, as he then served as Chief of the Tank Corps and Commander of the Tank School at Camp Meade.

As an instructor at French military training academies throughout the 1920s and 1930s, Jean Touzet du Vigier spoke with enthusiasm about the need to mechanize France’s armed forces. His advocacy served him well during World War II, when, after initially serving the German-backed Vichy France government, he joined the Free French resistance, eventually commanding the 1st Armored Division.

Touzet du Vigier’s troops were said to be among the first to reach the Rhine during the Allied advance toward Germany near the war’s end.

Bruce Magruder began his career with the U.S. Army in 1904, when he enlisted as a private. Through service that included two world wars and numerous other assignments, Magruder rose to the rank of major general.

When, in response to German tank doctrine, the 1st Armored Division was formed in 1940, Magruder was placed in command. The division remains active today and still carries the nickname that Magruder gave it: “Old Ironsides,” a reference to a renowned naval warship, the USS Constitution.

Corporal Donald M. Call joined the U.S. Tank Corps in 1918 and served in the 344th Battalion under then-Lieutenant Colonel George S. Patton, Jr. In September of that year, while Call and a fellow officer were engaging enemy troops near Varennes, France, their tank was struck by artillery. Although Call escaped the wreckage, he returned under heavy fire to rescue the officer and carry him to a secure location.

For his bravery and selflessness, Call became the first member of a tank crew to receive the Congressional Medal of Honor, which General John Pershing presented to him after the end of World War I.