According to the prologue to The Eagle, a second century Roman legion thousands strong was lost in battle somewhere in the wilds of north Britain. Lost with the Ninth Legion was a golden eagle, a symbol of Rome's might. The emperor Hadrian thereafter built his famous wall to mark off the border between the Roman Empire and no man's land. So begins The Eagle, a sword and sandals/western/buddy movie, about young Marcus Flavius Aquila (Channing Tatum), whose father led the Ninth Legion and lost the eagle. Marcus becomes a centurion, leads his men on a daring rescue mission, and is severely wounded, thus ending his military career.
While recuperating at his Uncle Aquila's villa, Marcus is impressed by the bravery of a slave named Esca (Jamie Bell), and saves his life. Uncle Aquila (Donald Sutherland) promptly buys the slave for Marcus. Esca is indebted to Marcus, and swears his loyalty (despite, presumably, the whole awkward slave/master thing). Then Marcus decides to take Esca to the north, to search for the lost eagle, and learn the fate of his father. Esca is a Briton, and speaks the language of the northern savages. Patrician Uncle Aquila cautions against the plan, warning Marcus that Esca will turn on him because "he is a slave." Uncle Aquila is kind of old school in his reasoning.
What follows, in this movie based on Rosemary Sutcliff's novel The Eagle of the Ninth, is a humorless adventure in which Marcus and Esca slog through the mud, eat rats, and get captured by the Seal people, a tribe of fur-wearing, mohawk-sporting warriors who cover themselves with grey mud and live in muddy huts. Scotland was apparently quite muddy back then, and the natives worked with what they had. I don't know how they kept the mud on with all the rain. The Eagle is basically a muddy cowboys and indians picture, with the Seal people playing the part of the fearsome Apaches. They dance, they hallucinate, they wear animal hides, they're excellent trackers, they're ruthless, and they can run like the wind. Horses are no match for the fleet-footed Seals. They don't much care for Romans.
What's interesting about The Eagle is the master-slave relationship between Marcus and Esca, and how that relationship subtly changes once the pair leave the confines of the Roman Empire. There's probably a fascinating story to be told about how relationships are altered by geography -- cross an arbitrary boundary like Hadrian's Wall, and the slave becomes free, and the master becomes a dependent. It could have been an interesting avenue for The Eagle to explore (particularly in light of current geopolitical complexities), but the movie doesn't make much of it, beyond supplying a few situations that test the loyalties of Marcus and Esca. The focus of the story is Marcus's fixation on restoring his family's honor by retrieving the golden eagle. Tatum gives a serious performance that had me convinced Marcus really cared about getting that eagle back, without convincing me that I should care actually about it myself.
And there's the catch with The Eagle. The movie hints at Roman atrocities, but it is ultimately sympathetic to the Romans, going so far as to refer to a massacre site as a "killing field" where Roman officers were sacrificed by bloodthirsty savages. It would have you side with Marcus, the slaveholder, but also with his noble slave Esca, who has every reason to hate Romans. The various anti-Roman tribes of the movie seem to have a genuine beef with the empire, but they are depicted as brutal primitives with wild, unruly hair and a single personality trait: they kill Romans.
Eventually, as such stories must, this one ends in a battle -- an epic battle, of course -- with lots of slashing, clinking swords and spears, and a great deal of splashing, since this battle takes place in a river. In many ways, The Eagle is a very retro movie, one in which actual actors rather than digital avatars slog through actual scenery -- dark, damp, cold, muddy scenery by the looks of it -- and fight without the assistance of special effects (other than a lot of fast editing and a little slow motion). They perform human-sized feats in what is a human-sized story. The Eagle aspires to be an old fashioned kind of adventure story of manly heroism (there's hardly a woman in the movie) and military glory. It might have been better, and more captivating, were it not so old fashioned in its simplistic, chauvinist depiction of the northern natives. The Eagle is retro and not revisionist in its history, but a little hindsight and cultural insight would have been enlightening.