When the Cadets are building the bonfire and celebrating the Armistice ending World War I, the background landscape is lush and green - not likely for November 11th.
Marty's farewell parade is held under overcast skies, but when Kitty and James are conversing at the same parade it is sunny and the sky is cloudless.
Interrupting the sermon, an announcement is made in the chapel regarding the Pearl Harbor attacks. On hearing the announcement, everyone spontaneously stands and sings a hymn, despite never being instructed to sing and never being told which hymn to sing.
In the scene where Martin meets Mary outside the gymnasium, he is carrying an armful of boxing gloves, and drops one or two. The dropped gloves change in number and position on the floor as the scene progresses, even Mary gets in the act, changing her position on the floor and relative to the gloves on the floor, and the hat on her head changing its tilt and position from scene to scene.
According to the plot line of the movie, Martin "Marty" Maher retired from the Army in the 50's (Eisenhower was President). In real life Maher retired from the Army in 1928 and stayed at West Point as a civilian employee in the athletic department and retired from that in 1946. He died on Jan. 17, 1961, at the age of 84 and is buried in the West Point cemetery.
In the film, Mary O'Donnell Maher dies sometime before Christmas 1944 while World War II is still raging. In real life, according to her headstone at the West Point cemetery, she died in 1948.
One of the big scenes in the film is when Marty's firstborn son dies. Marty and Mary Maher never had any children, stillborn or otherwise. The baby's death was Hollywood fiction.
According to the storyline, Maher arrived at West Point no earlier than 1902, but Herman Koehler was football coach from 1897-1900.
During the Army/Notre Dame football game of 1913, actors referred to Notre Dame as The Fighting Irish.
At the time the team name was actually The Catholics, and the name Fighting Irish was not adopted officially until 1927.
A previous comment about George Patton not having attended West Point is in error. Patton was enrolled at the academy from 1904 to 1909, graduating with the class of 1909. He was forced to repeat his plebe (first) year due to his poor academic performance, possibly caused by his lifelong struggle with dyslexia. Patton was enrolled at the Virginia Military Institute from 1903 to 1904.
In a previous post, it stated that George Patton had graduated from VMI, but did not attend West Point. In fact, while he did attend VMI, Patton graduated from West Point, Class of 1909; he was originally a member of the class of 1908, but was turned back a year because he was deficient in mathematics. Patton graduated 46th in his class of 103.
When Martin Maher, Sr is attempting to enlist in the Army, the official at the physical examining station announces "senior's" height as 6 feet, 4 inches, and his weight as 200 pounds. While the 200 pounds may have been correct, 6 feet 4 inches would have made "senior" a giant among men in 1917-1918. Later, when "senior" is standing next his son, "junior" is three inches taller than "senior," which would have made him 6 feet, 7 inches tall, which clearly he is not. However, it is clear that the men examining Martin Senior are humoring the old man by adding height to make him meet the weight standards.
On Armistice Day, when the cadets are celebrating the end of the war, all of the surrounding trees are full of green leaves. On November 11 in West Point's location, there would have been some combination of fall colors and already-bare trees.
When Marty picks his all time Army football team, he chooses Charlie Daly as quarterback. Daly was quarterback in 1901 and 1902, but was actually head coach in 1913 at the time of the Notre Dame game depicted in the film (not Koehler).
Another of Marty's all time players, Red Cagle, was - like Red Sundstrom, Jr. in the film, got married and was forced to resign from the academy before graduation. Unlike the movie character, instead of enlisting, Cagle turned pro and played in the NFL and he stayed married.
When Mary and Marty are at the cemetery putting flowers on Martin Mahers grave site, the time is supposed to be between 1941 and 1945 as the young cadet son of Betsy Palmer has not entered the service yet as an enlisted soldier. The tombstone directly behind Martin Mahers shows a death date of the occupant at 1952.
One of Marty Maher's many early duties as a recruit are various maintenance jobs, like cleaning up the cannonballs which are neatly piled as decorative material in front of the row of exhibition guns. Out of curiosity Maher tries to fit one inside a gun, but drops the ball quickly to the ground when an officer yells at him. This cannonball can still be seen lying separately on the same spot in a scene that takes place decades later.
When the Pearl Harbor announcement is made during Chapel, there was no reaction shown by the people in attendance. Granted this was West Point, but certainly such shocking news would have set off some emotion, with at least people looking at each other and commenting in low tones.
In the scene where Marty Maher (Tyrone Power) is giving swimming instructions to the West Point cadets, cadet James Nilsson 'Red' Sundstrom (William Leslie) dives into to the pool, swims the length of the pool and does a flip turn to swim a return lap. The flip turn in swimming was not in use in the era represented in this part of the film - pre-World War 1. The flip turn was developed by Tex Robertson of the University of Texas while training Adolph Kiefer for the 1936 Olympics.
Red's Medal of Honor that Kitty shows to Marty and Mary is the current design that goes around the neck. In the story, Red earned it during World War I and at that time the Medal of Honor was on a suspension ribbon like most other US medals. It wouldn't be redesigned for around the neck wear until 1944.
Cadets and officers are shown at chapel on December 7, 1941, a Sunday. An announcement is made that Japan has bombed Pearl Harbor. Pearl Harbor was attacked at 7:55 AM, Hawaii time, which is 12:55 PM New York time, with chapel services already having concluded.
When Martin and Mary Mahler leave with Dinny Maher to visit newly-widowed Kitty Sundstrom in 1918 or 1919, Dinny's car has an electric starter. The electric starter first appeared in Cadillacs in 1912 and was patented in 1915. However, mass use of electric starters didn't occur until the early 1920s. Although it is unclear what Dinny's car is (it doesn't appear to be a luxury automobile), the use of an electric starter is marginally correct, if at all.
When Mary Maher is dying on the porch, she hears the band music and is reacting like she can see the parade in the distance. However, she is sitting on the back porch of their quarters, which overlooks the Hudson River and not the parade grounds. Hence, she could not be watching the parade.