The conflict between faith and fanaticism—not to mention simple disbelief—lies at the core of this dark but curiously hopeful (though extremely violent) medieval tale about a journey gone terribly wrong. “Pilgrimage” isn’t really about one in the Chaucerian sense—the term, after all, usually refers to a trip to visit a holy place in the hope it will bring some redemptive effect, and the trek here involves the transport of a precious relic from western Ireland to Rome. But the essence of Jamie Hannigan’s script revolves around whether such sacred totems are worth the credence placed in them, or can effect justice in unexpected ways.

Following a prologue showing the stoning of Matthias, the “thirteenth disciple” who was Judas’ replacement, in Cappadocia, the scene switches to an Irish monastery, where a stone struck by lightning is venerated as being that which killed him, wielded by a man then incinerated by a bolt from the heavens. In 1209, a Cistercian named Geraldus (Stanley Weber) appears with a bull from Pope Innocent III, ordering that the strangely deformed stone be sent to Rome, where its power will be accessed to ensure the success of a crusade the pontiff is planning (presumably either the so-called Albigensian Crusade in southern France or the Fifth Crusade of 2013 to Egypt). The Abbot (Donncha Crowley) orders the reliquary, which had been buried to safeguard it against invaders, to be retrieved and assigns a group of four monks—Ciaran (John Lynch), Rua (Ruaidhri Conroy), Cathal (Hugh O’Conor) and young novice Diarmuid (Tom Holland) to accompany the relic and Geraldus to the port of Waterford for transport to England. The house’s mute but strong servant (Jon Bernthal), who washed up on shore years earlier and has remained ever since, will also go along.

For the first part of the journey, the group is protected by bowmen from a friendly Celtic tribe, but eventually they meet up with a force headed by the feudal lord (Eric Godon) who is leading the Norman effort to conquer the island. Elderly and desirous of absolution for his bloody life, he welcomes the travelers warmly and provides them with an ample squadron of knights. His son Raymond (Richard Armitage), the leader of the defenders, is, however, much less scrupulous in his religious practice, perhaps as a result of what he witnessed during the recent crusade that attacked the Christian city of Constantinople, where he picked up—from a priest, no less—a little knifelike device that causes excruciating pain when inserted into a foe’s abdomen and ever so slightly twisted, a tool he is not at all loath to employ.

The troupe will have hard going when most of their Norman protectors are called away on another mission and some hostile Celts attack. Two of their number will fall, one of them tortured to death, and only the intervention of the mute servant—who has a violent past—saves Geraldus, Diarmuid and Cathal. Recovering the relic, the four continue their trek with villains in close pursuit, and must try to escape on the river to Waterford, with the mute’s ability to hold off the attackers their only hope of success. In the end, however, the young, naïve novice will have to face off against the grimly determined Cistercian in what amounts to a contest between two very different conceptions of what faith entails.

“Pilgrimage” has a considerable number of virtues, from an attempt at historical accuracy that extends to the use of different languages—mostly English, but also some French and Gaelic, with occasional bursts of Latin (along with subtitles, of course)—to the magnificent vistas shot on location in luminous widescreen by Tom Comerford. It also boasts a convincingly grubby look (courtesy of production designer Owen Power and costumer Leonie Prendergast), a brooding atmosphere fashioned by director Brendan Muldowney, editor Maired McIvor and composer Stephen McKeon, and some expert acting from a committed cast, including Holland, who employs subtlety to make the novice a convincingly conflicted figure standing in contrast to Weber’s rigidly self-certain Cistercian and Armitage’s amoral, duplicitous Raymond.

There is, however, a central problem with the film: while it raises intriguing issues about religious belief, it also aims to be an action-adventure, a sort of thirteenth-century western, and the two parts don’t always mesh very happily. The periodic scenes of hand-to-hand combat and torture, though intensely played by Armitage, Lynch and especially burly Bernthal, are often so protracted and gruesome that they throw the film’s balance out of whack. Yes, the Middle Ages were a period of great brutality and copious bloodshed, but “Pilgrimage” is so determined to make that point over and over that the more thoughtful questions the embedded in the plot are often put on the back burner.

Despite its propensity to aim for the jugular rather than the brain, however, “Pilgrimage” proves an intriguing attempt at capturing the often contradictory spiritual and material realities of Europe’s so-called age of faith.