Since the Middle Ages, Christian pilgrims have been flocking to the Spanish city of Santiago de Compostela, built, it is said, on the remains of the Apostle James. But the past 20 years have witnessed an unprecedented surge in pilgrimage to Santiago.

Tired and muddy pilgrims rest heavy backpacks alongside the pews of Santiago de Compostela's soaring cathedral. They greet each other in restaurants, and pack Santiago's hotels. For centuries, these spiritual travelers, who arrive on foot, have been an unquestioned fixture of this medieval city. But never have there been so many, and they never came from so far away.

Over the past two decades, the recorded number of pilgrims trekking to Santiago de Compostela has soared from just 120 in 1982, to nearly 69,000 this year. An expert on the pilgrimage, Olivier Cebe, says the surge has been astonishing, particularly since most of the pilgrims are Europeans, and church attendance in Europe is plummeting.

Mr. Cebe is a member of the International Committee of Experts on the Road to St. James - the pilgrimage route from France that people started using in the Middle Ages. He says several reasons explain the growth in the number of pilgrims going to Santiago, who not only include Christians, but also Buddhists, Jews and even some atheists.

For one thing, Mr. Cebe says, the pilgrimage is easier, thanks to recent efforts to upgrade the French road to Santiago, and to establish new ones from other parts of Europe. Europeans are also increasingly interested in hiking, and in their cultural heritage.

But the interest in Santiago stretches well beyond Europe. And experts say it is evidence that more and more people are seeking their spiritual identity.

Today, pilgrims come from countries as diverse as Sweden, Sri Lanka, South Africa and the United States.

American Suzanne Da Rosa, 52, a poet from California, says she was drawn to the pilgrimage after seeing an art exhibit about it. She considers herself a non-practicing Catholic.

"I grew up in the '50s and '60s, when religion was always something you had to fear," she said. "Everything you do is a sin, and you can't get to God if you're a sinner. All my life I've been a sinner."

Mrs. Da Rosa says she did not intend to make a religious journey. But she ended up walking 800 kilometers to Santiago with her eldest daughter. She says the pilgrimage became a spiritual experience and a sheer test of endurance.

She is not alone. Up to 1,000 visitors arrive daily at Santiago's pilgrimage center during the peak months of July and August. They come here to receive their compostela from the Roman Catholic Church, a certificate attesting that they have walked at least 100 kilometers along the Road to Saint James. Even now, during a season of chilly rains, the center is full of travelers.

They include elderly walkers like 62-year-old Pamela Mathews. Mrs. Mathews, who lives in the Canary Islands, admits that her 250 kilometer trek was difficult.

"We feel the walk," said Pamela Mathews. "The exhaustion. The pain in the back carrying a heavy load. And the long steep, road that is hard on the knees. But it's a good feeling. You can't imagine what a good feeling it is to know you've come to the Compostela, that you've done the whole trip, and that now you're going to get the certificate."

Besides being a practicing Catholic, Mrs. Mathews had a special reason for making the journey. She says her brother is dying. She knows her pilgrimage won't make him better, but she hopes it will help ease his suffering.

Others, like Patrick Dubois, 46, insist they did not make the pilgrimage for religious reasons.

Mr. Dubois, who is from Bayonne, France, says the Road to St. James is simply a good hiking path. He says it helped him learn more about Spanish culture.

The man who oversees Santiago's pilgrimage office, Canon Jaime Garcia Rodriguez, doubts Mr. Dubois' explanation.

Father Garcia says pilgrims may not tell strangers the truth, but the truth is written on the church's registers. He says more than nine out of ten pilgrims who receive their certificates cite religious motives for their journey.

Indeed, the growing number of pilgrims to Santiago de Compostela is fueling the Catholic Church's ongoing effort to get some sort of religious reference into the new European constitution now being drafted. Next April, Church leaders will host a conference in Santiago, on Europe's spiritual roots. The timing coincides with the entry of 10 new countries into the European Union and with a special Holy Year of St. James in the Catholic Church.