A small Orthodox Christian congregation is finishing plans to build the first Byzantine-style church in Northern Virginia, modeled after a 6th-century Italian architectural masterpiece, the Church of St. Vitale in Ravenna. To help pay for the project, which could cost up to $2.4 million, the church plans to paint portraits of its most generous donors on an interior wall in spots historically reserved for saints, religious icons or an occasional emperor.

Holy Trinity Orthodox Church, a 20-year-old congregation of about 50 families, now rents space in a pool clubhouse in south Reston owned by the Reston homeowners association. Its neighbors are a karate school, Alcoholics Anonymous and a preschool. About 15 years ago, the church bought two acres in Potomac Falls, north of Route 7 and Northern Virginia Community College's Loudoun County campus. Construction of the 11,000-square-foot domed structure is scheduled to begin during the second half of next year, said the Rev. Paul Harrilchak, the parish priest.

"People laughed at me," Harrilchak said, referring to the fundraising plans to paint patrons on a side wall behind the church's altar. The church's founders and more recent leaders will also be memorialized on the walls, including the clergy. "I have to lose weight for my portrait," Harrilchak said.

Intricate mosaics of colored glass that depicted saints or other important figures, including wealthy church patrons, often filled the walls of ancient Byzantine churches, church officials said. Now, paint is a more common medium than glass tiles, which are expensive but "survive time like no other art," Harrilchak said.

"It's a much more poetic and symbolic way to be represented" than with a plaque, which churches often use to discreetly laud their benefactors, said Christos J. Kamages, the San Francisco-based architect who designed the Sterling church. Kamages has designed about 75 other Orthodox churches over the past 15 years.

Byzantine architecture is characterized by light-filled windowed domes that often bear the image of Jesus on the ceiling. A cross often sits atop the dome.

"From a symbolic standpoint, [the dome] represents eternity and heaven," said Kamages, principal architect for CJK Design Group. "From a physical standpoint, it takes light that God provides and brings it into the church at a 360-degree angle."

Stained glass, popular in some other ecclesiastical styles, is rarely used in Byzantine structures because it would interfere with viewing the icons painted on the walls or built into the walls in mosaics, Kamages said.

Unlike most Orthodox churches, which are organized around one ethnic group or country -- say, Russia or Greece -- Holy Trinity represents a range of ethnicities through its parishioners, who live in Fairfax and Loudoun counties, Harrilchak said. "We're just plain old Americans," he said.

Services are in English, and the entire congregation, not a separate choir, sings, unlike in other Orthodox churches, Harrilchak said. Because group singing is such an important part of Holy Trinity's services, the parish chose a special layout of the worship area.

"It has a center with people gathered around it," Harrilchak said, referring to the octagonal design of the main worship area. "It brings the voices together."

The new church is modeled after St. Vitale in both its shape and its memorialization of benefactors in art.

St. Vitale is famed for its octagonal architecture and its mosaics, which depict Emperor Justinian, who ruled the Roman Empire during the sixth century, and his wife, Theodora. Standing behind the emperor's left shoulder in one mosaic is "the guy who bankrolled the place, Julian [Argentarios]," said Harrilchak, identifying one of the Orthodox world's most famous memorialized rich guys.

Holy Trinity, like St. Vitale, will consist of two concentric octagons. Most modern Orthodox churches are square or rectangular, Orthodox church leaders said. The price tag of the Sterling church will depend on how many wings are included in the final plan, Harrilchak said. The structure includes multiple wings and halls, which form a "village" surrounding an atrium, Kamages said. "You can tell you're coming to a special place, not a shopping center or an institution," he said.

For Orthodox congregations, which often are smaller than other denominations in the area, building a stable following, finding a site and an architect and raising funds often are slow processes. Holy Trinity has raised about a quarter of the funds needed for the project.

Sts. Peter and Paul Antiochian Orthodox Christian Church in Potomac, which has about 350 families in its parish, waited 20 years before building its church, even holding services for a while in a Bethesda firehouse. To raise the $5 million to $7 million to build that Byzantine-style church, each family was asked to pay $4,000 over five years, said the Rev. George Rados, the parish priest.

When St. Nicholas Orthodox Cathedral in Washington, whose construction was completed in 1962, began having its interior finished during the early 1990s, the church allowed parishioners to pay to have their favorite saints painted on the walls. Other benefactors opted to pay for little plaques that went under windows. From 1991 to 1994, artists from a Russian Orthodox church in Moscow painted more than 200 sponsored icons on the walls, said the Rev. Constantine White, dean of the cathedral. The cathedral has Byzantine-style elements but is built predominantly in a Gothic, Russian style, church officials said. St. Sophia Greek Orthodox Cathedral in the District is another church recognized for its strong Byzantine style, most obviously its dome.

The Sterling church aspires to be more than just another building.

"We're establishing ourselves. Right now we just use a community room," Harrilchak said. "When we build what we build, it should be something of a landmark."

The Orthodox Christian church planned for Potomac Falls, with a dome, two concentric octagons and several wings, is modeled after an Italian treasure. It will be Northern Virginia's first church in the Byzantine style. The 11,000-square-foot Holy Trinity Orthodox Church could cost up to $2.4 million.