“Blood of Christ, inebriate me.” These words, from St. Ignatius’ prayer Anima Christi, are embla-zoned on one of the walls of the Basilica of the Sacred Blood (Heilig Bloedbasiliek) in Bruges, Belgium.

The basilica itself has been the center of devotion to the Precious Blood since at least 1255.

The church holds a vial purporting to be the precious blood of Jesus Christ. The relic is exposed for veneration every Friday. Each year, on Ascension Thursday — this year, that's May 24 — a gala procession with the relic wends its way through the quaint streets of this “Venice of the North.”

Pious tradition has it that, when Joseph of Arimathea took Christ's body from the Cross, he carefully preserved the blood mixed with water from Christ's side, as well as the blood from his nail wounds and, before dying, passed these precious relics on to his family.

Sporadic testimonies to the existence of relics of the precious blood appear from time to time in the Christian East, often associated with Constantinople. The fourth-century quest of Helen, mother of Constantine, for relics of the true cross is evidence that devotion to Christ's passion was strong.

There are two traditions accounting for the relic coming to the Belgian seacoast town of Bruges. An oral tradition claims that Thierry of Alsace, count of Flanders, was given a relic from Jerusalem with some of the precious blood by Baldwin III, his brother-in-law, in gratitude for services rendered during the disastrous second crusade. According to this tradition, Thierry returned with the relic to Flanders, entrusting it to the citizens of Bruges in 1150.

Although the oral tradition is the standard explanation for how Christ's blood came to Bruges, written documents do not mention the relic's being there until 1256. One list of relics, circa 1150, speaks of a relic of the precious blood in the Imperial Palace at Constantinople. On this basis, some say that the relic was a gift from the emperor to his daughter Jeanne, Countess of Flanders.

However it arrived in Bruges, Pope Clement V became aware of the cult in 1310, granting indulgences to those who participate in the annual procession that was already then underway. His bull, Licet, also claims that the clotted precious blood in the relic liquefies every Friday, a phenomenon not observed since 1388.

A doubting age may impugn the historicity of the relic, but, against such skeptics, Pierre Aspeslagh has an adequate reply: “As far as the origins of the relic are concerned, there is no proof of their historical authenticity. But one must not lose sight of the main point of the relic: namely, that as a symbol of Christ's ultimate sacrifice it has through the ages inspired and given comfort to millions upon millions of believers.”

Blood of the Lamb

It certainly inspired me. It was a moving experience to participate in Sunday High Mass at 11 a.m., when the relic was exposed for the faithful. Mass began with a procession of members of the Noble Fraternity and the Pious Fellowship of the Precious Blood, spiritual societies charged with promoting devotion to the relic. The relic is removed from a silver tabernacle and placed on the main altar during Mass. At the end of Mass, the congregation is blessed with the relic, which is then carried in procession to a raised side platform where the faithful can approach and venerate the relic, held in a crystal vial attached to a chain around the priest's neck.

It's hard to imagine any Christian not being moved by the scene. Many generations of Christians have grown in holiness in this place; here is a powerful and ancient reminder that “God so loved the world that he gave his only Son” (John 3:16).

The relic is exposed for veneration every Friday and, it seems, every Sunday after the 11 a.m. Mass. It is also exposed daily in the two weeks of the “Fortnight of the Precious Blood,” May 3-17.

The basilica itself, from the outside, is unprepossessing. The chapel dates from the first half of the 12th century and was dedicated to St. Basil the Great, though it was only raised to the status of basilica in 1923. Tucked into a corner of a square a block off Bruges’ main square, the smallish, grayish building does not compete with the grander ones — like the Gothic Hall — next to it.

The inside, however, is another story. There are two chapels, a lower and an upper. The lower chapel is Romanesque, its massive stone walls providing an air of solidity. Over the main altar is a golden pelican, recalling the legend that, in time of famine, that bird pierces its own breast to feed its young with its blood. The other statues in the lower chapel compellingly focus the mind on the Passion. Beautifully painted statues of Christ, Ecce Homo and in the tomb, are carried in the annual Ascension Day procession. The Pietà, with Mary in a purple robe and dark veil, holding the dead Christ, is simply impressive.

Much Ado about Ascension

The upper chapel, reached by a winding staircase, is where the relic itself is kept in a side altar. In contrast to the somber stone of the Romanesque lower chapel, the upper chapel is a Gothic riot of color. The eye is quickly riveted on the fresco behind the main altar. The cross stands center stage. Above, God the Father accepts his Son's sacrifice, while the Holy Spirit completes the Trinity. Some angels capture the blood draining from Christ while others carry instruments of his Passion. On one side of the Cross appears Bethlehem; on the other, Jerusalem. Sheep graze in the foreground, quenching their thirst from the living waters of the cross.

Ascension Thursday is the high point of Bruges’ year, when the relic is carried in procession through the medieval streets of this old center of the Flemish cloth trade. The day begins with veneration of the relic at the basilica. Mass at 11 a.m. in the cathedral follows. The procession takes place from 3-6 p.m. and is made up of four parts: medieval mystery plays depicting how the Old Testament prefigures Christ, the life of Christ, and how Thierry brought the relic to Bruges, followed by the procession itself. The day ends at 6 p.m. with Benediction.

If this powerful spiritual experience were not enough, Bruges welcomes visitors to wander its streets. One of the best-preserved Flemish medieval towns, Bruges boasts many beautiful churches. Since it has been designated a European Cultural City, lots of renovation work is underway, but it is still worthwhile visiting the cathedral and the Church of Our Lady. The latter holds a particularly beautiful marble Madonna and Child by Michelangelo, dating from 1514. The medieval Beguins also had a house in Bruges and their Beguinage, now housing a small Benedictine community, beckons.

Bruges is a city of canals and picturesque vistas, so bring lots of film. Also bring a good appetite, because Belgians love to cook. Mussels and rabbit in beer are local specialties. Belgian lace, tapestries and chocolate abound in Bruges, which is a day-trip for many people in the low countries, northern France and England.

For those who enjoy medieval and especially baroque music, Bruges also hosts a “Festival Musica Antiqua.” This year's festival will be held from July 28 to August 11.

I am annually tempted to return to Bruges for Ascension Thursday's Corpus Christi-like procession, which has been held there since at least 1291. They call it “Brugges Schoonste Dag” (Bruges’ Most Beautiful Day). For the tourist, it's an intriguing historic happening. For the pilgrim, it's an adventure in faith.

John M. Grondelski, a moral theologian, writes from London.