A season of religious holidays around the world moves into higher gear on Wednesday with the observance of one of the most important saints in the Orthodox Church, a person whose gift-giving legacy is partially tied to the birth of the Santa Claus legend in the U.S. and Father Christmas in the U.K.

But with the arrival of St. Nicholas Day – observed on Dec. 6 in Western Christian nations but on different December days elsewhere – also come questions about the future place Orthodoxy will occupy in the larger Christian world, say analysts.

Orthodox Christians exist in greater numbers today than in the past, yet represent a diminished share of Christians worldwide. Confined primarily to an aging Europe and strongly tethered to tradition, Orthodox Christianity may need to change its ways to remain relevant, say some practitioners.

"People are sending out a signal that they don't identify with structures of the past anymore and look for new forms of spirituality," says the Rev. Cosmin Antonescu from the Saint Andrew Romanian Orthodox Church in Potomac, Maryland.

Around 260 million people in the world today identify themselves as Christian Orthodox, double the number registered a century ago, according to a report from the Pew Research Center, a nonpartisan think tank. Russia alone has more than 100 million followers, while more than 95 percent of people in predominantly Orthodox countries such as Moldova, Georgia, Romania and Greece report keeping icons at home.

Yet, as popular as Orthodoxy is in Eastern Europe, this branch or Christianity seems to be losing ground in the overall Christian population. Today, Orthodox Christians represent only 4 percent of the world’s population. Additionally, Orthodox followers account for 12 percent of Christians worldwide, down 8 percentage points from the levels in 1910, according to the Pew report.

The reasons for this decline are many, and experts say they have to do with history and a more rigid administrative structure of the overall Orthodox community.

After the East-West Schism of 1054 between the Orthodox and Roman Catholic churches, Orthodoxism was left isolated in a declining Byzantine Empire. As countries broke away from the empire, Orthodoxism developed in a more decentralized way. “All nations identifying themselves as Orthodox have their own independent ruling,” Antonescu says.

While the Orthodox and the Catholic churches share many rituals and religious beliefs, experts say Orthodoxism seems to have done a better job at keeping its original traditions. When Catholics tried adapting the church to respond to new social needs, the Orthodox Christians focused on preserving their customs.

“We were the most constant church in Christianity, but failing to respond to people’s ever-changing needs made us lose ground in society,” Antonescu says.

Today, Orthodoxism remains concentrated in Europe, where 77 percent of Orthodox Christians still live, while Roman Catholicism expanded around the world.

“In the beginning we were the Byzantine Empire," Antonescu says. "Catholicism, the Western culture expanded in the world and brought Christianity to many places, while, after the rise of Islam, the Byzantine Empire focused on mainly defending against Islamic attacks until the fall of Constantinople. We weren’t given the same space as the Catholics were.”

Catholics have also arguably benefited from a stronger public presence by being represented by a singular leader, the pope, who has often been a well-known contemporary figure.

“Pope John Paul I became a significant global figure in his relatively short time; John Paul II was clearly a very visible figure globally, as well as Pope Francis is today,” says the Rev. Leonid Kishkovsky of the Church of Our Lady of Kazan, a Russian Orthodox Church in Sea Cliff, New York. “This all stems from the specifics of the Catholic Church with a figure in the bishop of Rome. This focus is very real and has been there all along but in the age of media popularity it has become very effective.”

According to the Pew report, a decline in Orthodoxism might also stem from declining demographic trends, with a lower fertility rate in Europe, where populations are growing older.

“Europe’s population has long been shrinking as a share of the world’s total population, and, in coming decades, it is projected to decline in absolute numbers as well,” the report shows.

In order to preserve not only its traditions but also its existence, experts say the Orthodox Church will need to look beyond Europe. That will be a challenging task, since the Orthodox Church is competing with more active religions that seem to be able to expand faster.

“Christianity is growing primarily in Africa and Asia and the Orthodox are not strong enough in those parts of the world to keep up with the demographic challenge of growth,” Kishkovsky says. “There is also a huge growth of Christians in China for instance. But the Chinese social and political situation is such that the primary growth – millions of adherents to Christianity – comes to the Protestants because their missions can be very informal and they move quickly among parts of the populations.”

Whether Orthodox traditions will stand the test of time is unknown. Priests say it's not uncommon for religions to transform and mold into something new, a development that shouldn't worry Orthodox followers.