VICTORIA FALLS, ZIMBABWE -- When the rally began, it had all the totems and gimcracks of a tribal celebration, modern Africa style.

The electronically amplified rumble of tribal drums washed over thousands of working-class people, almost all of whom were born into a tribe called the Ndebele. Mashed together in the dusty bleachers of a small-town soccer stadium, they had come to see the legendary champion of their tribe.

He arrived in a new, black Mercedes. In his right hand he held a black enameled walking stick, a symbol of chieftaincy. His presence prompted hundreds of women to dance and ululate. He was saluted by an elaborately feathered devilman on stilts.

At this rally, however, Joshua Nkomo did not pander to Ndebele affections. Instead, he delivered a thundering warning. He said, in effect, that tribalism was bleeding Zimbabwe to death.

"We are one people. You have got to accept that principle. We are one nation. There is no question of {one tribe} swallowing another," bellowed Nkomo. "Pick yourselves up, pull up your socks and say we shall be one."

Nkomo, white-haired and jowly, a hulking 300-pound presence in a tent-like powder blue shirt, is the founding father of the political party that represents the Ndebele, a minority group that since Zimbabwe's independence has been beaten and beggared by tribal violence.

The "Old Lion," as he is sometimes called, helped lead the guerrilla war that broke the back of white rule in this country, which was once called Southern Rhodesia.

Because of who he is, Nkomo's address to the Ndebele faithful here at Victoria Falls, one of a series of such speeches he has delivered in recent weeks, was a watershed in the politics of Zimbabwe and of black Africa.

On a continent where tribal allegiance remains the sine qua non of power politics and civil war, Nkomo has agreed to do what no African leader of his standing has done before. He has voluntarily signed a unity pact that dismantles a tribal-based political party. He has merged the party of the minority Ndebele with the party dominated by the country's majority Shona-speaking tribal grouping.

At age 71, Nkomo has buried his life-long ambition to lead Zimbabwe and gone on the road to persuade the Ndebele that national, not tribal, unity is their only hope for ending years of killing in Matabeleland. Only with unity, he preaches, can this region expect to get its share of government money for schools, health clinics and jobs.

After the rally, when he was sprawled -- exhausted -- on a bed in a Victoria Falls hotel room, Nkomo admitted that his crusade for unity was "a bit late."

He said he should have made his peace years earlier with Robert Mugabe, leader of the rival Zimbabwe African National Union (ZANU) and president of Zimbabwe. Nkomo said he had ill-served Zimbabwe by encouraging its people "to be divided by a political party."

"It was a waste of time, of lives and of resources. We were stupid," said the man who used to call himself "Father Zimbabwe." "Now, rather than saving my face, I am saving the face of my country."

As a sweetener for signing the unity agreement, Nkomo was rewarded by Mugabe with an appointment as a senior minister in the government, a powerful, patronage-laden position he said he plans to use to bring jobs and development to Matabeleland.

In the past two decades, Nkomo often was criticized for being a bit too willing to make deals with the white rulers of Rhodesia and with certain foreign businessmen, deals that strengthened his personal power or benefited him financially. Roland (Tiny) Rowland, head of the British-based Lonrho conglomerate, which has large holdings in Zimbabwe, is believed to have been a major benefactor of Nkomo prior to independence.

However, several of Nkomo's past critics now say they believe that the aging politician's campaign for unity is a genuine effort to heal wounds that his ambition and his political party helped open.

The darkest stain in the development of Zimbabwe, Africa's youngest and, in many ways, its most impressive black-ruled nation, is violence in Matabeleland. That violence, and the tribal tensions that underlie it, has echoes across Africa.

The map of modern Africa blurs and confuses many of the tribal boundaries that demarcated the continent prior to colonization in the late 19th century. The contemporary borders have more to do with European land greed than with African history. Yet, in the name of continental stability, modern Africa lives within the colonial lines.

This roping together of tribal groups, which often are estranged by differences of language, religion and culture, fuels what may be Africa's most intractable and destructive political problem.

Zimbabwe's grim passage of violence in the 1980s is a primer on how tribalism can catch fire, destroy economic development and scar a nation's international reputation.

Yet the recent unity agreement here and the willingness of a leader like Nkomo to swallow his ambition suggests that the disease of tribalism in Africa is not incurable.

In independent Zimbabwe, the killing grew out of personal rivalry between Nkomo and Mugabe.

Mugabe, eight years younger than Nkomo, was once an understudy in the nationalist movement that Nkomo headed. The Zimbabwe African Peoples' Union (ZAPU) represented both the Ndebele, who make up only about 19 percent of the population, and the Shona-speaking tribes, about 77 percent of the population.

Mugabe, sensing an opening for himself, helped lead a splinter movement in the 1960s. His ZANU party lured away the Shona and left an embittered Nkomo as a minority leader.

During the seven years of the Rhodesian civil war, the two men led separate guerrilla armies. At independence, Nkomo lost the national election to Mugabe. The vote, of course, split on tribal lines.

While clinging to hopes of one day leading Zimbabwe, Nkomo accepted Mugabe's conciliatory offer of a position in the Cabinet. There also was a grudging merger of the two men's guerrilla armies.

It did not work. In 1982, Mugabe's men discovered a large cache of Soviet arms on land owned by Nkomo and his supporters. Suspecting that the "Old Lion" was plotting a coup, Mugabe fired Nkomo from his Cabinet post. He also detained several of Nkomo's former military chiefs.

In retaliation, soldiers who had fought for Nkomo deserted the national Army. They fled into the Matabeleland bush, where the line between dissidence and banditry quickly blurred. Villages were burned, tourists murdered, white farmers terrorized.

Mugabe dispatched an all-Shona Army unit to root out the dissidents. They had little success. Instead, they went on a spree of terror.

"It was tribal genocide," said Father Hebron Wilson, a Catholic priest in Matabeleland who led protests that helped force Mugabe to rein in the Army.

The Army's aggressiveness sparked a reaction familiar across much of Africa -- more violence. According to local authorities, "dissidents" since 1982 have killed 10 to 12 people a month. Much of the killing was aimed at intimidating civilians into providing food and shelter for the attackers.

It was the murder of white people, however, that garnered worldwide publicity for Matabeleland. Since 1982, 66 whites have been killed. The most gruesome incident occurred last November at a mission school. Sixteen missionaries and their children were hacked to death with axes.

Since Nkomo and Mugabe signed their unity agreement on Dec. 22, there has been an extraordinary lull in the violence. "There is a whole new attitude here," said Hebron. "The violence seemed to stop automatically on Dec. 22. The very same {government} soldiers who stopped people from going to and from their village, who accused them of being enemies of the state, now don't ask questions. They let the people go as they wish."

Exuding an optimism that appears to be shared by many Zimbabweans, especially here in Matabeleland, Hebron said that the unity agreement may one day become a more important historical event for this country than independence.

"The war brought independence, but the people of Matabeleland were not free," said Hebron. "This unity makes them feel that they finally are a part of Zimbabwe."

For years, Nkomo and his party have disowned the "dissident" violence. He said it was misnamed by the government and he blamed it on "bandits" more interested in loot than politics.

In the interview in Victoria Falls, however, Nkomo conceded that prior to his signing the unity agreement, some of these "bandits felt they could have power in the party" by committing acts of violence.

"It was small-time political games, and unity cuts the ground out from under them," Nkomo said.

While unity could lead to a substantial and perhaps even permanent reduction in tribal violence in Zimbabwe, it also means that the country has turned its back on multi-party democracy.

As a result of the unity agreement and changes last year in the country's British-style parliamentary system, the 63-year-old Mugabe is now virtually unchallengeable as leader of Zimbabwe.

Yet many people here, Nkomo included, say they are willing to take their chances with a man like Mugabe, who after eight years in power has proven himself to be a relatively moderate and adaptable leader. The alternative to a one-party state headed by this moderate man, they say, is not western-style, multi-party democracy with all its checks and balances. It is more killing.

At about the same time that the unity agreement was signed, it began to rain in Matabeleland. The rains broke a five-year drought.

The dovetailing of unity and rain has not gone unnoticed by Ndebele farmers. "We had bloodshed for years, and that was our rain," said Mike Hove, a retired Zimbabwean diplomat and folk historian of the Ndebele.

Hove said that, by custom, the Ndebele pray to their ancestors in time of drought, asking them to lobby God for rain. When the Ndebele quarrel too long and bitterly, he said, "It is thought that it sours relations between us and our ancestors. They will not intercede with God."

It is now clear to many Ndebele, Hove said, that unity pleases the ancestors, who have put in a good word with God about rain.