The relics of St. Juliana now repose in the bright yellow Church of St. Nicholas on the Embankment, perched precariously on a steep bluff. As I enter to pay my respects, two babies are being christened. The portly priest, sweaty and impatient with the young parents and godparents, shows less interest in making the rite understandable than in getting it over with.

"Come on, come on, undress them," he barks. "How can I put them in the water like this? Let him hold the candle. No! In the right hand! What are you doing?" The babies scream, the cameras flash, the parents fuss, and soon the baptisms draw to a close.

On the other side of the church, a middle-aged woman with a white kerchief tied fiercely around her head berates me for photographing the relics of St. Juliana. "Did the priest bless you to take photographs?" she demands. "Photographing without a blessing will only bring evil!"

I recognize her kind from my years in the Soviet Union. There were always women like her in the few churches that were open in those days, women who scrubbed the floors, tended the candlestands, and stood through all the services when Soviet disapproval had frightened off everyone else. In a sense, they nursed the church through its long incarceration. They were the custodians of propriety and custom: Stand like this! Face the altar! Cover your head! Cross yourself! They were insufferable, but the church owes them a great debt. So I do what other Russians do when confronted by these vigilantes: I meekly bow and put away my camera.

Obedience and ritual have ruled the Russian Church ever since the pivotal day in 988 when Prince Vladimir, ruler of Kievan Rus, ordered his people to be baptized in the Dnieper River. According to the legend familiar to every Russian, Vladimir had sent envoys abroad in search of a faith for his pagan nation. Those dispatched to Constantinople returned home awestruck by the Eastern Greek ritual they had witnessed in the Hagia Sophia, then the largest cathedral in the world. "We knew not whether we were in heaven or on earth," they reported.

The religion imported by Prince Vladimir shaped the Russian nation and was, in turn, shaped by it. Orthodox monasteries became the spiritual, economic, cultural, and at times, defensive core of the nation. The churches that spread through Russia were awe-inspiring in their magnificence and immutable in their ritual. To this day the language of the church is an archaic but mellifluous Old Church Slavonic. Priests in their glittering vestments are separated from the congregation by an elaborate icon screen, and choirs sing most of the liturgy, often with hymns by Russia's greatest composers. For worshippers, the experience is as otherworldly as a Baptist service is direct and unadorned.