Goofs

After Becket averts trial and climbs the stairs, he is followed by a baron who draws his sword. Becket stands with his left side angled toward the baron. After the cut to long as he leaves the room, Becket is clearly angled toward the baron with his right side.

Thomas Becket was a Norman (Thomas Bequet), not a Saxon. Jean Anouilh based the play's script on Augustin Thierry's 1825 work "The History of the Conquest of England by the Normans", which presumed that Becket was a Saxon. Anouilh admitted he'd learned the truth after completing the play, but decided to leave it as is because it made for a better story.

The film seems to assume that Henry and Thomas speak English. The French girl Marie is clearly depicted as speaking a different language. Becket and Henry were native French speakers, and Henry spoke no English at all.

Henry II makes fun of his son at dinner, calling him Henry III. Henry II 's son, Henry, was crowned in 1170, but he was known as the Young King, and died six years before his father. Ordinals were used later.

Eleanor of Aquitaine says she will complain to her uncle, the emperor, about Thomas Becket's murder. She was not related to Frederick Barbarossa. She was also a devout Catholic, and Frederick was excommunicated in 1160, and was in a power struggle with the Pope, establishing several rival antipopes before reconciling with Rome in 1177. Eleanor also says she will protest to her father, who died when she was 15, long before she met Henry.

The Royal court dress depicted is from the 15th century, not the 12th century.

The story takes place in the late 12th century, but King Henry's children play in 15th century armored helmets.

In the opening scene, set in 1173, "Dies Irae" plays as Henry walks through the cathedral. Monks chant the same song in the excommunication scene, set in 1164. The hymn was composed by Thomas of Celano, who lived from 1200-1260.

The floors in the castle's great hall are bare flagstone. In the 12th century, floors were covered in rushes to absorb spills, garbage, and animal feces. When they got too filthy, fresh rushes were thrown down on top. Henry was known for fits of fury in which he would fall on the floor and "chew the rushes."

When Becket writes the message for Brother John to deliver to King Henry, he writes on modern paper with acid content, which was developed in the 19th century.

In the film, Henry's court is in England. In real life, Henry II's primary residence and capital was Chinon, nearly 186 miles (300 kilometers) southwest of Paris. England was only one land in Henry's empire, which included most of modern-day France.