After years of striking out, the Yankees — baseball’s most successful franchise — will finally get a new home, the most expensive stadium ever built.

Yesterday, on the 58h anniversary of Babe Ruth’s death, the Yankees’ brass along with Mayor Bloomberg, Governor Pataki, and local politicians broke ground on a new billion-dollar stadium, just north of their existing home in the south Bronx.

The team expects the stadium, which will have a capacity for 53,000 fans, will be completed in time for the 2009 season, when the Mets also hope to open a new ball field in Queens.

For many years, Yankees officials have flirted with the city about building a new home. The existing stadium, known ubiquitously as the House that Ruth Built, was erected in 1923 when the Yankees moved east from the Polo Grounds in Upper Manhattan.It was renovated in the early 1970s, but it is still the third oldest stadium in baseball.

The dimensions of the current field, known for the short right field porch, will remain intact in the new design, which will replicate many structural details, including the famous white frieze along the roofline. Monument Park, which contains the brass memorials of Yankee greats, will move behind center field in the new stadium. It will have more seats on the lower level and less in the upper deck than the current configuration, more luxury boxes and improved concessions.

The Yankees’ principal owner, George Steinbrenner, told the crowd of supporters gathered yesterday: “We are happy we are able to do this for the Yankees, and we are happy we are able to do this for you people.”

A journalist who focuses on stadium construction, Neil DeMause, estimated that the current deal, including transportation and infrastructure contributions and tax breaks, would cost the city, state, and federal governments more than $400 million.

“The public is putting up a smaller share than in other city’s deals, but it is the most expensive baseball stadium in history,” Mr. DeMause said.

Mr. Bloomberg said yesterday that the new stadium would inject private capital and add jobs in the south Bronx, one of the city’s poorest communities.

“The Yankees’ $800 million investment in this stadium represents a huge vote of confidence in the future of this community,” Mr. Bloomberg said.

Discussions about moving the Yankees to a new stadium in New Jersey began in 1985 during the Koch administration. In 1993, during the tenure of Mayor Dinkins, the Yankees first considered moving to the West Side of Manhattan. In 1998, that plan was rekindled by Mayor Giuliani, a tenacious Yankee fan. Later in Mr. Giuliani’s second term, negotiations commenced for a new stadium in the Bronx.

Last summer, within days of the rejection of the proposed football stadium on the West Side, both the Mets and the Yankees, along with city officials, announced plans for new ballparks. Soon after, the biggest hurdle of the current Yankees plan, the alienation of more than 22 acres of Bronx parkland on which the new stadium will be built, sailed through the state Assembly. The project quickly moved through the city’s land use process and the City Council gave the final nod this April.

The president of the Real Estate Board of New York, Steven Spinola, said the new stadium deal was in the works for years and that yesterday’s groundbreaking is related to the Yankees’ recent financial success. Attendance has soared in recent years and they have been the beneficiaries of a lucrative cable television deal.

“The Yankees are in financially probably the best shape of their existence, and the city is in great shape too,” Mr. Spinola said. “You also have to give some credit to the borough president for agreeing to move some parks.”

The president of the Bronx, Adolfo Carrion, fielded community criticism for backing the plan that was rejected by the local Community Board last year in an advisory vote.

Yesterday, outside of the area fenced off for the groundbreaking, activists gathered to protest the destruction of parks and what they said was an overly generous incentives package for the Yankees.The city will pay to replace the parks with 27 acres of new parks scattered around the neighborhood.

On Tuesday, a state court denied an opponents’ attempt to block construction. A park advocate, Geoffrey Croft, called the judges’ decision flawed, and said that a coalition of project opponents planned to appeal the state decision and file a federal lawsuit against the development.

“This is a corporate retention deal gone wild.The Yankees did not have to consider any other alternatives,” Mr. Croft said.