The film was an Anglo-American co-production. It was released in the U.S. and Canada on 11 February 2011, and in the United Kingdom and Ireland on 25 March 2011.
As a historical matter, the purported disappearance of the Ninth Legion in Northern Britain is a subject of debate and dispute (see Legio_IX_Hispana § Theories about the Ninth's disappearance for details.)
In the year AD 140, twenty years after the Ninth Legion disappeared in the north of Britain, Marcus Flavius Aquila, a young Roman centurion, arrives in Roman Britain to serve at his first post as a garrison commander. Marcus's father disappeared with the eagle standard of the ill-fated legion, and Marcus hopes to redeem his family's honour by bravely serving in Britain. Shortly afterwards, only Marcus's alertness and decisiveness save the garrison from being overrun by Celtic tribesmen. He is decorated for his bravery but honourably discharged due to a severe leg injury.
Living at his uncle's estate near Calleva (modern Silchester) in southern Britain, Marcus has to cope with his military career having been cut short and his father's name still being held in disrepute. Hearing rumours that the eagle standard has been seen in the north of Britain, Aquila decides to recover it. Despite the warnings of his uncle and his fellow Romans, who believe that no Roman can survive north of Hadrian's Wall, he travels north into the territory of the Picts, accompanied only by his slave, Esca. The son of a deceased chieftain of the Brigantes, Esca detests Rome and what it stands for, but considers himself bound to Marcus, who saved his life during an amphitheatre show.
After several weeks of travelling through the northern wilderness, Esca and Marcus encounter Guern, a Roman born Lucius Caius Metellus, one of the survivors of the Ninth Legion, who attributes his survival to the hospitality of the Selgovae tribe. Guern recalls that all but a small number of deserters were killed in an ambush by the northern tribes – including Esca's Brigantes – and that the eagle standard was taken away by the Seal People, the most vicious of the tribes. The two travel further north until they are found by the Seal People. Identifying himself as a chieftain's son fleeing Roman rule and claiming Marcus as his slave, Esca is welcomed by the tribe. After allowing the Seal People to mistreat Marcus, Esca eventually reveals that his actions were a ploy and helps his master to find the eagle. As they retrieve it, they are ambushed by several warriors, including the Seal Prince's father, the chief of the tribe. Marcus and Esca manage to kill them. Prior to dying, the chief reveals that he tortured and killed Marcus' father. Marcus does not understand Celtic and asks Esca to translate, but Esca never reveals the fate of Marcus' father. With the aid of the Seal Prince's young son, they escape from the village.
The two flee south in an effort to reach Hadrian's Wall, with the Seal People in pursuit. Marcus, slowed by his old battle wound, orders Esca to take the eagle back to Roman territory and even grants the reluctant slave his freedom. Freed, Esca still refuses to abandon his friend and instead heads out to look for help. He returns with the survivors of the Ninth Legion just as the Seal People catch up with them. The legionaries, wishing to redeem themselves, accept Aquila as their commander and prepare to defend the eagle standard. As an example to those who would betray their people, the Seal Prince kills his young son in front of Esca, Marcus, and the legionaries. He then orders his warriors to attack. A battle ensues, in which the Seal Prince and all his warriors are killed, along with most of the Ninth Legion soldiers. With the enemy defeated, the bodies of both Britons and Romans are laid out by the victors. As Marcus commends their valour, he lights a funeral pyre for Guern. As Guern is cremated, Marcus, Esca and the few survivors of the Ninth return to Roman territory, where Aquila delivers the eagle to the astonished governor in Londinium. There is some talk of the Ninth Legion being reformed with Marcus as its commander. But when Marcus and Esca wonder what they will do next, Marcus leaves the decision to Esca.
An alternative ending is featured in the DVD. Marcus decides to burn the eagle standard on the altar where the final battle occurred, instead of delivering it to the Roman governor. He tells Esca that he does this because the eagle belongs to the men who fought for it. Marcus and Esca are then shown approaching Hadrian's Wall on foot and talking about their plans for the future.Channing Tatum as Marcus Flavius Aquila
Jamie Bell as Esca
Donald Sutherland as Marcus's Uncle Aquila
Mark Strong as Guern/Lucius Caius Metellus
Tahar Rahim as Prince of the Seal People
Denis O'Hare as Centurion Lutorius
Douglas Henshall as Cradoc
Paul Ritter as Galba
Dakin Matthews as Legate Claudius
Pip Carter as Tribune Placidus
Ned Dennehy as Chief of the Seal People
Principal photography began on 24 August 2009 in Hungary, which doubles for what was later to become England. In October, production moved to Scotland, where filming took place in Wester Ross and at Loch Lomond, among other locations. The film was made for around £15 million by producer Duncan Kenworthy's Toledo Productions for co-financiers Focus Features and Film4. Kevin Macdonald directed from a script by Jeremy Brock, who adapted the 1954 historical adventure novel of the same name by Rosemary Sutcliff. The director of photography was Anthony Dod Mantle, production design was by Michael Carlin, the costume design was by Michael O'Connor, and Justine Wright edited the film—her fifth for Macdonald. At the 62nd Cannes Film Festival in May 2009, The Eagle of the Ninth secured distribution deals "for every global market".
Macdonald intended the film to be historically authentic, but as little is certain about the tribes that the Romans encountered—they were generally Celtic peoples, though some may have been Picts—he made concessions. For example, the tribespeople spoke Gaelic, even though the language probably did not enter widespread use in the region until the 5th century AD; Pictish is the more likely language to have been spoken at the time. "It's the best we can do," Macdonald said. "All you can do is build on a few clues and trust your own instincts. That way, no one can tell you you were wrong." Only 1% of Scots speak Gaelic, limiting the talent pool to just 60,000 people. By August 2009, several Gaelic-speaking boys had auditioned for the role of a boy of the Seal people, aged nine to twelve, but without success, so Macdonald held open auditions in Glasgow for the role. It was eventually given to nine-year-old Thomas Henry from New Barnsley, Belfast, who had been educated in Irish Gaelic.
Macdonald described his view of the Seal people:
They were a more indigenous folk than the Celts, who were from farther south ... They were probably small and dark, like the Inouit [sic], living off seals and dressed in sealskins. We are going to create a culture about which no one knows much, but which we will make as convincing as possible. We are basing it on clues gained from places like Skara Brae and the Tomb of the Eagles in Orkney, so that we will have them worshipping pagan symbols, like the seal and the eagle. The reason they have seized the emblem of the Roman eagle from the legion is because to them it [was] a sacred symbol.
Achiltibuie, a village in northwest Scotland, was used as a filming location for the "Seal People". Filming started in Achiltibuie on 7 October 2009, and finished on 15 October 2009. The main location was Fox Point, Old Dornie. The Pictish village which was constructed at Fox Point was used on most days of the filming. Other sites included Achnahaird beach, where a horse chase was filmed, and Loch Lurgainn. Macdonald intended to use locals as extras. This was a success with many locals appearing as extras after going to castings in nearby Ullapool. Their roles included "Seal Warriors", "Seal Princesses" and "Elders".
In a reversal of Hollywood films about the Roman Empire, Macdonald said the Romans are played by American actors and Rome's enemies by British actors, while the British actors Paul Ritter and Mark Strong used American accents to play their Roman characters. The Romans are played by Americans "to achieve a little contemporary symbolism", with Bell using a neutral English accent.
According to Channing Tatum, the actors trained 4–5 hours a day for each role.
Although the film mostly stuck to the plot of Sutcliff's novel, there were a few modifications and condensations, e.g. it introduced a few violent scenes into what had been a novel written for older children.
The Eagle received mixed reviews, with the review aggregation website Rotten Tomatoes reporting that 39% of critics gave the film a positive review with an average score of 5.3/10, based on 143 professional reviews. The site's consensus stated, "The Eagle has a pleasantly traditional action-adventure appeal, but it's drowned out by Kevin Macdonald's stolid direction and Channing Tatum's uninspired work in the central role." Metacritic gave the film an average score of 55/100 based on 35 critical reviews. The reception by audiences was similar, with audiences giving the film an average score of 'C+' according to CinemaScore.
Roger Ebert gave The Eagle three stars out of four saying that "it evokes the energy of traditional sword-and-shield movies" and praising its realistic battle scenes and limited use of CGI.
The film had a worldwide gross of $35,467,108 as of 9 May 2011, higher than its $25 million budget.
In the United States, The Eagle was released on 11 February 2011, in 2,296 theatres. It grossed $8,684,464 during its opening weekend, ranking 4th behind Gnomeo and Juliet, Justin Bieber: Never Say Never and Just Go With It.
The Eagle was released on DVD and Blu-ray Disc on 21 June 2011.