For Roman Catholics, to step into an Eastern Church is to enter the past. The medieval-looking icons adorning the walls, the celebrants' rich robes, the ornate gold work, and the wafting incense -- all recall a time long ago, a time before Vatican II swept the Western Church clean of such trappings. Yet for Eastern-rite worshipers, neither theirs nor ours is a dead and dusty past. Those following the Byzantine rite, in fact, enjoy a liturgical tradition established by the early Church in Constantinople, and it is this tradition that is followed by the majority of Orthodox and Eastern-rite Catholics even today.

In Canada and the United States, for instance, Ukrainians, Ruthenians, Slovaks, Romanians, and Melkites all follow the Byzantine rite.

The Eastern Churches in union with Rome have the same basic beliefs as Roman Catholics. They show it, however, in a fashion shaped by a different culture, language, and history.

According to the Byzantine tradition, God is at the center of all things while human beings are on the periphery. (Roman Catholics, on the other hand, focus more on their personal connection with God.) Added to this emphasis is a strong link with the founders of the Church. Unlike Roman Catholics, the Eastern faithful have retained a more visible evidence of their religious progress through the ages, reminding them that they are only the latest chapter in the story of creation.

Eastern Churches also have retained a more mystical bent than Rome. A stronger tradition of monasticism and contemplative life, for example, has provided the East with a vigorous spirituality. These factors add up to a distinctive expression of faith in God. And this distinctiveness is apparent as soon as one approaches a Byzantine church.

According to a book authored by the Canadian Catholic bishops called The Byzantine Ukrainian Rite, the architecture of the church building tries to recreate, albeit in imperfect human fashion, a bit of heaven on earth. Its opulent, other-worldly style is an attempt to take parishioners away from their earthly cares and give them a sensual experience of being with God.

Usually, Byzantine churches are shaped like a Greek cross, topped with about 5 domes -- but sometimes as many as 13. The largest dome, most often over the middle of the nave of the church, represents Jesus Christ hovering over his people. The four smaller domes represent the four Evangelists (Matthew, Mark, Luke, and John), reflecting the Church's role in bringing the Gospel to the world. Some churches have 12 smaller domes, each symbolizing one of the Apostles.

Inside, the Byzantine churches, like the Roman Catholic ones, are divided into three areas. But there are obvious differences. For Eastern-rite Catholics, the vestibule represents a connection to the outer world. In the early churches, catechumens (those preparing to become Christians) were instructed here.

Next, over the nave, hovers a large, intricate chandelier symbolizing the light of Christ. And while many modern Byzantine churches have pews and kneeling pads in the nave, their tradition is to stand during prayer. (Kneeling was reserved for penitential occasions, mainly during Lent.)

The sanctuary will bring back memories for those Roman Catholics old enough to recall the Church prior to Vatican II. Here, the priest faces the altar, his back to the congregation.

The most notable difference between a Roman Catholic sanctuary and an Eastern one is the iconostasis. The royal doors, symbolizing the gates of heaven, serve as a barrier between the nave and the altar and tabernacle. While the iconostasis appears to be a wall between God and the people, it is really both a window and a mirror, according to Father Mark Melone, a Melkite Greek priest. "Those depicted on the iconostasis," says Fr. Melone, "have lived this present life and now reflect to us the life beyond. They are the 'living stones' who, like us, are built into the Church."

The icons arranged upon the iconostasis appear in a hierarchical order, with Christ in the center leading up to God. As a result, they tell much about the relationship of the Trinity to the saints and Church founders. Of all the icons, those of the Mother of God, the Theotokos (God-bearer), are especially revered in the Eastern Churches. Though human, Mary's physical closeness to God lifts her above normal existence. Often, the Theotokos is depicted as the Mother of God of Tenderness, holding the Christ Child cheek-to-cheek.

Though the sacraments are inherently the same in both the West and the East, notable differences in timing and expression are evident. For instance, the sacraments of initiation (Baptism, First Communion, and Confirmation) are -- in the Eastern-rite Churches -- performed simultaneously.

Then, too, Eastern Churches traditionally have ordained married men, though bishops are chosen from among the celibate priests. And while married men are still ordained in many countries and among many of the Churches, the Ukrainian Catholic Churches in Canada and the U.S. have observed a ban on ordinations of married priests that was decreed by Rome in the 1920s.

The Mass itself, or Divine Liturgy in Eastern parlance, brings together Byzantine beauty, solemnity, and joy in the celebration of the Eucharist. To be sure, Roman Catholics will recognize its resemblance to their own liturgy, though it is longer, more opulent, and tradition-laden. The priest, assisted by a deacon, begins with the preparation of the gifts, which includes an incensing of the altar. This takes place prior to the public part of the Mass, which features what is known as the Little Entrance, a procession around the altar with the Gospel book to start the Liturgy of the Word.

The Liturgy of the Eucharist has its own procession as well, called the Great Entrance, in which the gifts are brought to the altar. Holy Communion is received under both species, with small cubes of consecrated Bread commingled with the consecrated Wine and placed into the mouth of each communicant with a small spoon.

While still other differences between the East and the West exist, there simply are too many to mention. Indeed, some of these differences are slowly disappearing in North America. The Julian calendar, for example, gradually is being replaced in most Eastern-rite Churches by the Gregorian calendar. Nevertheless, the adherents of the Byzantine rite zealously protect their traditions. For Eastern-rite Catholics, such practices are powerfully symbolic, embodying the very relationship such Churches enjoy with God.