MEXICO CITY — Vicente Fox was sworn in as president of Mexico today, ending 71 years of ruling-party domination in a moment that some Mexicans have hoped for — and others have feared — for generations.

Standing before a joint session of Mexico's Congress, Fox took the oath of office in the first peaceful transfer of power to an opposition party in Mexico's history.

"This is a great day for me and for Mexicans," Fox said as he left his hotel this morning.

Democracy dawned with a spurt of ash from the Popocatepetl volcano that overlooks the capital and an earthquake that slightly shook tall buildings in Mexico City. There were no reports of damage.

Fox entered office to an enthusiasm that blurred, at least momentarily, ideological lines and political interests across the nation. Even the long-silent Zapatista rebel leader Subcomandante Marcos, hunkered down in the jungle of Mexico's southern Chiapas state, saw some hope.

"For us, the nightmare ends today," he wrote. "Another could follow, or it could be a new dawn. We will do everything in our power to make that dawn flourish."

Fox began the day unlike any president in the past 130 years — with a visit to a basilica to pray to the Virgin of Guadalupe, Mexico's patron saint. All Mexican presidents had shunned religious displays since 18th century struggles against the Roman Catholic church's privileged role in the country.

He spent several moments kneeling at the altar in silent prayer, often gazing up at the image of the Virgin, before leaving to shouts of "Viva Vicente!" from other worshippers.

His motorcade threaded slowly through crowds of people waving from the sidewalks and sometimes had to stop as police cleared the way.

Fox then had an open-air breakfast with street children in Mexico City's notorious Tepito neighborhood. Wearing a blue work shirt and jeans, Fox chatted and laughed with children, handing out tamales and pouring cups of atole — a traditional drink based on corn starch — as mariachis played.

He ducked into a slum apartment in Tepito to change into his suit before being driven to Congress for the inauguration.

Members of Fox's Cabinet, packed with businessmen, began to take over their new posts. Interior Secretary Santiago Creel, the man Fox picked to lead negotiations to reshape Mexico's shattered political landscape, assumed his duties in a midnight ceremony. Defense Secretary Gen. Ricardo Vega and Attorney General Gen. Rafael Macedo also were preparing to take office as the new day began.

Fox himself was to be sworn in around midday.

Like other new leaders in Latin America — a region long riven by sharp extremes of right and left — Fox came to power as an ideological hybrid, an energetic populist who courted everyone from street kids to corporate tycoons.

That style, and the enthusiasm for Mexico's step toward democracy, was reflected in Fox's inauguration ceremonies.

His first planned stop of the day was a breakfast with homeless children. Then it was on to a series of events that had him rubbing elbows with such obvious opposites as Cuban President Fidel Castro and U.S. Secretary of State Madeleine Albright — and many others in between. Leaders of 15 Latin American countries were expected.

Fox will need all of the above on board if he is to rebuild Mexico as promised. He inherits a country filled with poverty and corruption — but also one with a new hope for the future.

Hundreds of thousands of people were expected at the rallies Fox planned on his three-day inauguration tour of four Mexican cities. He will meet with peasants, Indians, artists and intellectuals.

Fox has denied that his grandiose inauguration marked a return to the stark contrasts of state opulence and widespread poverty that prevailed before Mexico's 1910 revolution.