In the heart of what is now Seoul’s busiest shopping district, the store at Myeongdong Cathedral is doing a brisk trade in Pope Francis T-shirts.

At just $7 a pop, they’re flying off the shelves, according to the shop assistants. So, too, are statuettes of the smiling pope — his head disproportionately larger than his body, like a bobble-head toy — and books in Korean about him.

This might be considered ironic, given that the pope, who arrives Thursday in Seoul on his first visit to Asia, is expected to warn against unchecked consumerism and widening social inequality.

But it also reflects the unusual quality of the visit, the first by a pope to East Asia in a quarter-century, at a time when the Catholic Church is hungry to make further inroads in a region it sees as presenting a huge opportunity for growth.

(Interactive Graphics: Where do the Catholics live?)

Catholic worshipers attend a Mass on Aug. 4 at Myeongdong Cathedral in Seoul. Pope Francis is scheduled to visit South Korea on Thursday. (Ed Jones/AFP/Getty Images)

About 12 percent of the world’s Catholics live in Asia, and most of them live in the Philippines. But the number of Catholics has increased sharply in South Korea, even in the face of competition from fast-growing Protestant churches.

Pope John Paul II visited South Korea twice, in 1984 and 1989, but Pope Benedict XVI never made it east of Jordan.

Pope Francis has had an abiding interest in Asia — as a young Jesuit, Jorge Mario Bergoglio hoped to be sent to Japan. He is coming to South Korea to deliver the closing Mass on Sunday at Asian Youth Day, a gathering of young Catholics from almost 30 countries across the region, to be held in the central part of the country.

In Seoul, he will hold a huge open-air Mass in the center of the city and a smaller one at Myeongdong Cathedral. Pope Francis will also beatify 124 Korean Catholics killed during the 18th and 19th centuries, during the Chosun dynasty. All the while, he will get around not in a bullet­proof Popemobile but in a Kia Soul — a modest South Korean car in line with his preference for humble over flashy.

“If you hoard material possessions, they will rob you of your soul,” the pope wrote on Twitter last week.

About one-third of South Korea’s population identifies as Christian, and about 1 in 10 — or 5.4 million people — is Catholic.

The pope’s visit is set to be much greater than the sum of its parts.

Souvenirs on sale at Myeongdong Cathedral in Seoul ahead of the pope’s visit to South Korea. (Anna Fifield/The Washington Post)

“He has really become a phenomenon, a figure who speaks to human rights and the interests of the poor, and this is true in Asia, too,” said Lionel Jensen, a professor of East Asian cultures at the University of Notre Dame.

But spreading Catholicism in South Korea will not be easy — especially when Protestant churches are putting so much effort into growing their congregations.

“The Catholic Church has been very focused on providing social services and trying to play a positive role in Korean society,” said Tark Ji-il, professor of religion at Busan Presbyterian University. “But Protestant churches have been focusing on numbers.”

Nor will it be particularly easy to grow the faith across Asia, especially where South Korea’s neighbors are concerned

North Korea bans religion of any sort — meting out the harshest punishments for those worshiping any god whose name isn’t Kim — and declined the South’s invitation to send Northern Catholics to this week’s events. There were an estimated 50,000 Catholics in North Korea before war broke out on the peninsula in 1950.

Still, the pope’s visit will be timely given what is going on across the sea in China, Jensen said. Christians there are reporting a new wave of religious persecution, with crosses being stolen and churches­ being destroyed.

Chinese authorities even announced this month that they would introduce their own “Chinese Christian theology,” apparently part of an effort to control the strong growth in the number of Christians in the communist country by interpreting the Bible on their behalf.

While the Catholic population in the Asia-Pacific region has more than doubled from a century ago, it is still a paltry 3 percent, according to a Pew Research Center report published last year. That contrasts with the relative saturation in Europe and Latin America.

In South Korea, the Catholic Church has a particularly special place in many hearts because of the role it played during the country’s often-brutal democratization process during the 1970s and 1980s. Myeongdong Cathedral became a refuge for pro-democracy and labor union activists — including future president and Catholic adherent Kim Dae-jung — during this time. They were rallying against Park Chung-hee, the strongman president whose daughter Park Geun-hye — nominally a Catholic, baptized “Juliana” — is the country’s current leader.

“But since democracy was established, Koreans have become very materialistic and people’s values have changed,” said Father Mattias Hur Young-yup, a representative for the Seoul Archdiocese. “Modern society has become too competitive, and the gap between rich and poor has become too big. That’s leading to a lot of problems in our society.”

Income inequality in South Korea has worsened as the economy has grown — and opened itself to the forces of global trade while keeping social spending low. The country also has one of the highest suicide rates and highest abortion rates in the developed world.

The church could help put Koreans right again, Father Mattias said in an interview.

“Catholicism played a large role in democratizing this country, and now Catholicism and religion can play a huge role in putting the values system right,” he said.