Major General Terry de la Mesa Allen Sr. (April 1, 1888 – September 12, 1969) was a senior United States Army officer who fought in both World War I and World War II. Allen was a decorated World War I veteran, where he commanded an infantry battalion at the relatively young age of 30 in 1918 and was wounded twice, and, after America's entry into World War II in late 1941, he commanded the 1st Infantry Division in North Africa and Sicily from May 1942 until August 1943. He was later selected to lead the 104th Infantry Division as divisional commander, a post he held until the war's end in 1945.

Early years

Allen was born in Fort Douglas, Utah, to Colonel Samuel Allen and Consuelo "Conchita" Alvarez de la Mesa. Allen's family had a long line of military tradition. Besides his father, Allen's maternal grandfather was Colonel Carlos Alvarez de la Mesa, a Spanish national who fought at Gettysburg for the Union Army in the Spanish Company of the "Garibaldi Guard", officially known as the 39th New York Volunteer Infantry Regiment, during the American Civil War.Arlington National Cemetery Allen grew up in various military bases because of his father's military career and in 1907, received an appointment to the United States Military Academy (West Point) in New York.Time Magazine: Terry Allen and His Men Unlike most American World War II generals, Allen was a Catholic.p.161 Snape, Michael God and Uncle Sam: Religion and America's Armed Forces in World War II Boydell & Brewer Ltd, 21 May 2015

Early military career There were three certain factors which affected Allen's performance at West Point and which would lead up to his dismissal. One of them was that he began to stutter and soon fell behind in his classes. Another was that he was held back a grade in his second year because he failed mathematics. Finally, he failed an ordnance and gunnery course.

Allen enrolled and attended the Catholic University of America in Washington, D.C., and earned a Bachelor of Arts degree in 1912. He joined the United States Army once more and after passing the competitive army officers exam, was commissioned a second lieutenant in the cavalry and assigned to Fort Myer, Virginia. In 1913, he was reassigned to the 14th Cavalry Regiment at Eagle Pass, Texas, and served there until 1917. During this time, he pursued and captured ammunition smugglers and served on border duty. He was promoted twice; on July 1, 1916, to first lieutenant and on May 15, 1917, to captain, almost six weeks after the American entry into World War I.

By this time, despite being "woefully ignorant of the trench warfare of the western front", Allen had gained some valuable knowledge during his tour on the border. He had learned how to lead and to command men. He knew what it was to engage in a firefight and, having acquitted himself well, could be confident that he would perform under pressure.

During his years as the son of an officer at different encampments, he had mingled freely with the rough-hewn enlisted men and their children. Even then he held no rigid distinctions—favoring neither those who commanded nor those who followed. When he was on active duty with the 14th Cavalry, he lived in the field with the troopers, isolated from the niceties of a well-established army post, and his appreciation of fellow soldiers regardless of rank could only have been enhanced.

World War I Just over a year on from America's declaration of war on Germany and her official entrance into World War I, Allen still remained in the United States, having spent most of that time training the huge numbers of draftees that came pouring in. Desperate to escape, and fearing that he would spend the war at home training troops, he sought a transfer. He ultimately got his wish, although it was not quite in the form which he had expected, when he was assigned to the 315th Ammunition Train. The unit was attached to the 90th Division, with the key responsibility of transporting artillery ordnance to the front lines. The division's commander was Major General Henry Tureman Allen (no relation) and the division itself was scheduled to go overseas to France. Allen was ecstatic and wrote home, "I cannot understand my good fortune to jump over the heads of quite a few fellows who [out]rank me. [I] am in the artillery now and though I hate to take off the crossed sabers it's anything to get to France."

According to rumour, Allen showed up at a school for infantry officers the day before a class graduation. When the commandant of the school began to hand out certificates to the graduates, Allen lined up with them. When confronted with him, the commandant said, "I don't remember you in this class." "I'm Allen. Why don't you?" was his reply. Without further ado, Allen was given the certificate and became a temporary major.

Allen was assigned to the 3rd Battalion of the 358th Regiment, which was also part of the 90th Division which had been sent to reinforce the American Expeditionary Forces (AEF) on the Western Front. Allen led the battalion into battle at St. Mihiel in mid-September and later during the Meuse–Argonne offensive, the largest battle in the history of the U.S. Army. It was during this brief but bitter campaign that Allen began to develop his preference for night operations. "Night attacks for a comparatively short advance can be accomplished under his worst conditions. The surprise effect saves lives", he wrote.

Allen remained with the AEF in France until the Armistice of November 11, 1918. By this time, he wrote in a letter back home, "I can't help but weaken when I look at the size of some of my companies. Some of them cut down to 40% and only 3 officers left who went over the top with me at St. Mihiel. I'm using my 3rd adjutant now. Two of them were killed, poor fellows." On the day of the Armistice, although Allen and his division had received orders to halt its operations, other American units, notably the 2nd, 79th, 81st and 89th Divisions, continued attacking until 11am, when the Armistice was due to come into effect.

Allen was awarded a Silver Star and a Purple Heart for his actions during the war. The citation for his Silver Star reads as follows:

He then served with the Army of Occupation in Germany until 1920 when he returned to the United States.

Between the wars After Allen returned to the United States, his temporary rank of major was reverted to captain until July 1, 1920, when he was promoted to the permanent rank of major. He served in Camp Travis and later in Fort McIntosh, both located in Texas. In 1922, Allen was assigned to the 61st Cavalry Division, in New York City. He also competed in the polo tournament at the 1920 Summer Olympics, winning the bronze medal.

He continued to take military related courses, among them: an advanced course at the U.S. Army Cavalry School, Fort Riley, Kansas; a U.S. Army Command and General Staff School at Fort Leavenworth, Kansas (where he did not distinguish himself, graduating 221st out of a class of 241 while Dwight D. Eisenhower, a fellow student who, unlike Allen, had not served overseas during the recent war, graduated first); a course at the U.S. Army Infantry School at Fort Benning, Georgia and an interim course in infantry command with other divisions. It was while he was at the Infantry School that he came into contact with Lieutenant Colonel George C. Marshall, the assistant director at the school, who came to form a very high opinion of Allen, giving Allen very high marks on his efficiency report. He believed Allen was qualified to attend the U.S. Army War College and concluded his efficiency report by stating, "By training, experience and temperament, highly qualified as a leader" and "qualified as of now as commanding officer of a regiment and in wartime a division." In 1928, he married Mary Frances Robinson of El Paso, Texas with whom in 1929 he had a son, Terry Allen Jr.

In August 1934 Allen went as a student to the Army War College, from where he, together with some eighty other fellow students, graduated in June 1935. While he was there his group studied several different topics. It also dealt with a paper war game dealing with the possibility of a second global conflict. On August 1, 1935, Allen was promoted to lieutenant colonel and became an instructor at the U.S. Army Cavalry School at Fort Riley, Kansas. He wrote and published "Reconnaissance by horse cavalry regiments and smaller units" in 1939.Reconnaissance by horse cavalry regiments and smaller units; by Terry de la Mesa Allen; Publisher: The Military service publishing company (1939); ASIN: B0006AOR0S

On October 1, 1940, during World War II (although the United States was still neutral at this point) George Marshall, now a full general and the U.S. Army Chief of Staff, promoted Allen to the rank of brigadier general (without ever holding the rank of colonel) and placed him in command of the 3rd Cavalry Brigade. From April–May 1941 he commanded the 2nd Cavalry Division. He then became the assistant division commander (ADC) of the 36th Infantry Division, an Army National Guard formation from Texas. The 36th Division was commanded by his good friend, Brigadier General Fred L. Walker, who, like Allen, was also a non-West Pointer. During this time Marshall wrote to a fellow officer, Lieutenant General Hugh A. Drum, then commanding the U.S. First Army, about Allen, describing him as "outstanding as a leader" and believing that Allen "can do anything with men and officers, though unprepossessing in appearance and apparently casual in manner."

World War II In May 1942, five months after the Japanese attack on Pearl Harbor and the subsequent German declaration of war on the United States, Allen was promoted to the rank of major general and given command of the 1st Infantry Division (also nicknamed "The Big Red One" due to its distinctive "1" insignia), a Regular Army formation. Like all divisions in the U.S. Army at the time, the 1st, having been originally organized in 1917 during World War I as a square division of four infantry regiments−in the case of "The Big Red One" these were the 16th, 18th, 26th and 28th, together with various supporting units−it had now been reorganized as a triangular division of three regiments of infantry instead of four (with the 28th Infantry Regiment transferring to the 8th Infantry Division), again with an appropriate number of supporting units.

Allen's 1st Infantry Division was soon sent to the United Kingdom where they underwent further combat training, which included training in amphibious operations. Allen and his ADC, Brigadier General Theodore Roosevelt Jr. (son of former President Theodore Roosevelt), distinguished themselves as combat leaders. Allen's brash and informal leadership style won him much respect and loyalty from the men in his division, who wholeheartedly adopted his emphasis on aggressiveness and combat effectiveness rather than military appearances. Another notable officer under his command was his chief of staff, Colonel Norman Cota, who would later become a major general and be remembered for his leadership on Omaha Beach during the invasion of Normandy on June 6, 1944, more commonly known as D-Day.

North Africa