Muslims were said to be training to attack Christians. Christians were said to be stockpiling weapons for an assault on Muslims. Fears of an all-out religious melee became so rampant last year that the archbishop of the Orthodox Christian church sent spies to a mosque thought to be harboring Islamic fighters.

“They were saying through the loudspeakers that ‘the soldiers of Allah are brave’ and telling Muslims to take action,” the archbishop, Abba Athanasium, said recently.

But then something unusual happened across the rolling green mountains in this part of Africa so defined by its volatility: nothing.

Since the Sept. 11, 2001, terrorist attacks, concern about Islamic extremism has been rising across the Horn of Africa, and notably in Ethiopia, a country where Orthodox Christianity is often associated with national identity but whose population is nearly half Muslim, according to Ethiopian demographers and U.S. officials.

Ethiopian Prime Minister Meles Zenawi cited radicalism within an Islamic movement that had taken power in neighboring Somalia, and its potential to spread across the border, as the main reason Ethiopia invaded that country in December.

Just two months earlier, an incident near the southern Ethiopian town of Jima underlined those fears. Though the motive remains a matter of debate, several days of violence between Muslims and Christians swept through the area, ending with 19 people killed and five churches and 600 houses burned, according to a government report.

Police eventually contained the violence, but the gruesome aftermath of a massacre of several worshipers in a church was captured on videotape by an evangelical Christian relief group investigating the situation. Soon, bootlegged copies — including an edited version superimposed with such phrases as “Look at what they are doing to us” — began showing up in markets across the country, including more than 300 miles away in Dese, where vendors began selling them alongside Britney Spears videos.

The rumors followed: The next religious battleground would be Dese, a long, narrow city of a thousand rusted roofs situated in a crevice in the grassy Tossa mountains.

In many ways, Dese is a hodgepodge of a place, where streets are framed by arched doorways built by Arab traders, striped awnings hung by Italian occupiers, and boxy lacquered mini-malls with cafes where large-screen TVs are tuned to al-Jazeera and Randy Travis songs occasionally drift out of open doors.

Above all, though, Dese is a symbol of Ethiopia’s peaceful religious intermingling, a characteristic that is found to varying degrees across a country where nationalism or ethnicity or even devotion to soccer tends to trump religious fervor.

For centuries, Muslims and Christians here have lived in the same neighborhoods, celebrated each other’s holidays, intermarried and blended religions with indigenous beliefs. Relationships are cemented through such Ethiopian institutions as the idir — groups of neighbors, often religiously mixed, that raise money to pay for funerals.

In Dese, it is easy to find someone like Zinet Hassen, a Muslim woman wearing a long, black burqa who said, nonchalantly: “My uncle converted to Christianity but there was no stigma.”

It is a kind of coexistence that has endured despite the fact that Orthodox Christians have historically had the upper hand in Ethiopia, politically and economically. In the 1880s, for instance, Muslims in Dese were forced to convert to Christianity, an edict the emperor issued as a means of consolidating power.

Under the socialist Dergue government of the 1970s and ’80s, religious expression was discouraged, and it became difficult to acquire land to build churches and mosques. The situation changed dramatically when Meles took power in 1991 and lifted those sorts of restrictions.

Since then, mosques have been springing up across the country, many funded by Saudi or Yemeni financiers, along with a kind of competition with the Orthodox church, and to some extent, evangelical Christian churches, which receive funding from U.S. religious groups.

In Dese, four new mosques have been built in recent years, and more are under construction. Orthodox Christians have kept pace with five new churches since 1993. “We have plans to do more,” the archbishop said. “We’ve now applied to build six more churches in Dese in every direction.”

Since the Sept. 11 attacks, the competition has been heightened as a strain of more fundamentalist Islam has woven through Ethiopian society and, in Dese, taken hold in some mosques. One mosque in the city now barricades the area at prayer time. Some young men have begun growing their beards long, and more young women are wearing burqas, sights that were once rare.

Imam Omar Adam, for instance, complained that a man was ridiculed by some Muslims for worshiping trees, which is forbidden by Islam.

Even some idirs have separated along religious lines. And here and there, friendships have fallen apart.

Helen Alebachew, a Christian, said she and a Muslim woman grew up playing at each other’s houses but hardly even look at each other anymore.

“Out of the blue, suddenly she joins this group of extremists,” said Alebachew, 19, using a label Christians here often apply to more devout Muslims. “Even in school she stopped saying hi.”

Given these tensions, some Muslim leaders in Dese say they have been accused of encouraging radicalism, a claim they tend to dismiss as Christian propaganda.

“Me, I’m not fundamentalist,” said Ahmed Mousa, who runs the 80-year-old Showber Islamic school in Dese, where children are still taught with the help of whips. “I’m Ethiopian.”

But he acknowledged a shift, particularly among young Muslims, which he and other leaders described not as fundamentalism but as a desire to become more devoted and, perhaps, to recover a religion their parents lost.

“They are now detaching themselves from the old culture,” Mousa said. “The mixed culture is degenerating.”

And so when the violence erupted in Jima last October, the news arrived in Dese amid a changing atmosphere.

With rumors swirling, the mayor — whose first name, Jemal, is Muslim and last name, Kassahun, is Christian — called a meeting of the city’s religious leaders, including a Muslim sheik who has a Christian uncle, and a Christian pastor who has a Muslim grandfather.

“There were these confused people, Christian-to-Muslim converts, who tried to instigate people,” the sheik, Hadji Mustafa Mohammed, said about the rumormongers. “But we took measures and brought it to a halt.”

The leaders agreed that the violence in Jima must have been the fault of outsiders, or motivated by an Ethiopian political group trying to use religion to destabilize the area, which a government investigation also concluded.

The reaction has been similar elsewhere in Ethiopia, where the notion that the violence could have been instigated by Ethiopian Muslims and Christians has remained somehow unthinkable.

“When I first saw the tape, I couldn’t finish it,” said Aissetu Barry, a Christian and director of the Interfaith Peace-Building Initiative in Addis Ababa, referring to the scenes of carnage on the Jima video.

“I thought it must be external people, because there is no way we could have done this to ourselves. I saw the tape with a Muslim friend, and she cried, too,” Barry said.

As they tried to understand what had happened, people in Dese considered their own families, friendships and neighborhoods.

“We Christians and Muslims have been together in good times and bad times,” said Endris Ahmed of the local Islamic Affairs Council. “We decided that this is not going to be spoiled.”

The tensions subsided, and life went on in Dese, where the tinny, amplified Muslim calls to prayer and rhythmic readings from the Orthodox Bible float across each dawn and dusk.

One recent evening, Nurye Seid commented that the speakers seemed to have become louder lately, a sign, he figured, of the kind of low-level religious competition that he is beginning to feel within his own family.

The high school geography teacher, a Muslim, married a Christian woman in a civil ceremony last year, and now they have a son nearly a year old.

So far, however, they have been unable to decide whether to raise him as a Muslim or Christian. In fact, they have not even given the child a name.

Seid’s parents are hoping for Abubakr. His wife’s parents are pulling for Abel.

For the time being, though, they are calling the child Abush, which, roughly translated, means baby.

“We have arguments sometimes,” said Seid, adding that neither he nor his wife is particularly religious. “I think different cultures are more difficult to resolve, but this religious issue can be solved through discussions.”