Medieval indulgences worked something like modern frequent-flyer plans. For making the pilgrimage in a normal year, a pilgrim got a third of his sins struck off the books. For participating in a religious procession in Santiago, he got a 40-day free pass from purgatory, plus a 200-day bonus if the procession was led by a bishop. One hundred days free for going to Mass on the Monte de Gozo. And a plenary indulgence for going to Santiago in a Holy Year (like 2004, in which the July 25 Festival of St. James falls on a Sunday) or for any pilgrim who happened to die on the road. Not a bad deal, all things considered.

We latter-day pilgrims may have Internet-enabled gps cell phones, but the medieval pilgrims knew exactly where they were going and why. Modern pilgrims can't help envying their predecessors' clarity of moral purpose. On the other hand, I'm pretty sure that they would have envied our Gore-Tex. Dante defined the true pilgrim as one who tackled El Camino de Santiago, but his definition is too broad for some purists. So are the requirements of the Catholic Church's Pilgrim Office, which grants a certificate called the Compostela to anyone who has walked the last consecutive 100 km or biked the last 200. Camino puritans insist that a real pilgrim must walk with a pack, sleep in refugios and eat humbly. Bicycle pilgrims are beneath notice. Pilgrims on horseback are exotic, pilgrims with cars a travesty. It isn't going to Santiago that matters so much, it's how deeply you suffered to get there. After all, suffering is what separates a pilgrim from a tourist. If medieval pilgrims sought answers to prayers, modern pilgrims are just seeking answers. But after the first few hundred thousand steps, I have forgotten the question.

Day 3, 65 km — Pamplona
I've learned to my horror that El Camino is actually designed to prevent pilgrims from eating well. I can't stop for a real meal during the day because my quivering legs might refuse to get moving again. At night, the better restaurants generally open at 9 p.m., but the refugios lock their doors at 10 p.m. I'd have to sleep outside or sneak in through a window like a delinquent teenager. And unwashed wine grapes, it turns out, can give you the runs.

But visions of food propel me. The knowledge that Chef Manoli Arza and her sisters were waiting in Pamplona to teach me the secret

It isn't going to Santiago that matters so much, it's how deeply you suffered to get there

to preparing the pillowy white beans called pochas is the only thing that gets me over the Pyrenees. I had first tasted this Navarra specialty at their restaurant Hartza five years ago, and I have been craving them ever since.

My greed finds swift retribution on El Camino. I talk so much about my pocha paradise that other pilgrims start craving them too. After three days of slogging over the hills, I finally walk up to the door with my new friends Karla, a Brazilian engineering student, and René, a recently single Belgian-Canadian grandfather. Hartza is fancier than I remember, but maybe that's because I'm self-conscious about wearing muddy boots into a nice restaurant. Fortunately, the delicately simmered pochas are every bit as fluffy and ethereal under their feisty garnish of red and green peppers and chorizo as I dreamed on the hungriest kilometer. But my long-anticipated cooking lesson had disappeared. An even more voracious pilgrim named Olivier, a Frenchman living in England, had copied the address and gotten there first. The sisters assumed that he was the pilgrim food writer expected that day and taught him their special recipe. I resolve to talk less and walk faster.

Day 8, 184 km — Najera
Unless a pilgrim knows where to look, El Camino can be a purgatory of the menú peregrino, the pilgrim's fare usually consisting of limp salad, tough greasy steak or spaghetti, and the Spanish equivalent of a Twinkie. Some linguistically challenged pilgrims learn only the word bocadillo and condemn themselves to six weeks of sandwiches. Few things are more painful for me than watching people eating sandwiches in a world-class tapas bar. As a multilingual pilgrim, my biggest job is translating menus. Some pilgrims are curious to try new dishes, but many just want to avoid accidentally ordering things like blood pudding or pony carpaccio.

By now, the vegetarians are getting desperate. Spain has had a long history of giving short shrift to people who would rather not eat pork. Spanish food is relentlessly carnivorous. In desperation, most vegetarian pilgrims end up closing their eyes or compromising. Passing by a roadside snack bar on the way to Nájera, I meet a young, blond pilgrim who is busy devouring a shortbread cookie the size of a small platter. She says it's the best vegetarian food she has found in days. I don't have the heart to tell her it's a tarta de manteca (cake of lard).

Day 11, 251 km — San Juan de Ortega
By the time I cross the River Oca gorge and follow the yellow painted arrows over the steep, thickly wooded mountains, I have mastered the basic pilgrim's prayer. When the road is going up or the sun going down, it's a beseeching, "Please, please, please …" When the road is gentle and the sun is rising, it's a fervent, "Thank-you, thank-you, thank-you." Once a rich and powerful spiritual complex, San Juan de Ortega now consists of a church, a monastery and the grimy Bar Restaurante Marcela, all standing in a row — a one-stop pilgrim center. Calixtus, the curate's spotted white dog, is known to follow pilgrims for days until someone fetches him or sends him home in a taxi. He is nosing about the gravel lot, probably sniffing out his next guide to Santiago.

The church of San Juan de Ortega is sacred to civil engineers and barren women. Queen Isabel la Católica came here twice to take the fountain waters and pray for a miracle. Of her five children, two were named Juan and Juana, certainly a ringing endorsement for the local fertility treatment. As a childless woman hitting her mid-30s, I consider taking a sip from the miraculous fountain myself, but I chicken out — having put off kids this long, it's become a habit. I wash my clothes in it instead.

Our spare underwear is flapping on the clotheslines in front of the church when the first visitors arrive to see the monastery's other miracle. By 5:30 p.m., the aisles are crammed with pilgrims and bus tourists, and the parish priest has to bang on the podium to remind the noisy crowd that we are in the house of God. The miracle of San Juan de Ortega is that a 12th century architect had the technical savvy to design a tiny window that catches a ray of sunset exactly on the spring and fall equinox. That feat, plus building some of the pilgrim roads and bridges we walk today, earned a civil-engineering sainthood for Juan de Ortega. But when the sun begins to set, scientific explanations fly out the window, and the miracle leaves us gaping in wonder like any pre-Copernican congregation.