BOSTON (Reuters) - When redecorating his home some years ago, financier Henry Kravis sold a painting by John Singer Sargent to the Museum of Fine Art in Boston.

Boston Cardinal Sean O'Malley (C) signs the guest book during a brief tour of the Museum of Fine Arts, Boston's new Art of the Americas wing with U.S. Senator Scott Brown (L) (R-MA) and MFA Director Malcolm Rogers in Boston, Massachusetts November 12, 2010. The $345 million wing opens to the public on November 20. REUTERS/Brian Snyder

The painting -- “Charles Stewart Sixth Marquess of Londonderry, Carrying the Great Sword of State at the Coronation of King Edward V11 August 1902, and Mr. W.C. Beaumont, his Page on That Occasion” -- is one of thousands of works that will now be displayed at the museum’s new Art of the Americas Wing, which opens to the public on Nov 20.

“This is the kind of Sargent that is a real opportunity for a museum because it is not the kind of Sargent that is popular in commercial terms,” museum director Malcolm Rogers told a news conference on Friday to launch the wing.

Hanging close to the “Lord Londonderry” painting is Sargent’s immensely popular 1882 painting, “The Daughters of Edward Darley Boit.”

Sargent is one of hundreds of American artists represented in the Art of the Americas Wing, including John Singleton Copley and his famous portrait of American patriot Paul Revere, from 1768.

The expansion, which increases the museum’s square footage by 28 percent, was 10 years in the making and represents the biggest initiative in the world focused on American art and culture, Rogers said.

The $504 million project involved $345 million for the building and $159 million for endowment of programs, positions and annual operations. Fundraising was completed shortly before the financial market crisis of late 2008.

The four-floor building contains 53 galleries that include works of art from North, Central and South America spanning three millennia, more than doubling the number previously on view. They include paintings, furniture, sculpture, musical instruments, textiles, fashion and jewelry.

“We are trying to give a full arc of the story of the Americas,” said Elliot Bostwick Davis, chair of the Art of the Americas Department at the museum.

The new wing allows numerous masterpieces to be displayed that have been in storage for decades due to the lack of large-scale exhibition space.

One of those pieces is Thomas Sully’s 1819 painting “The Passage of the Delaware,” depicting George Washington leading his troops across the Delaware River to surprise British forces; and John Singleton Copley’s “George IV When Prince of Wales” from 1809.

Among the wing’s prize possessions is the 1788 painting “King Lear” by Benjamin West, which Rogers said was once one of the most famous paintings in the world.

“It was an absolute classic that I wanted back here,” he said.

The new wing and adjacent glass-enclosed Ruth and Carl J. Shapiro Family Courtyard, was designed by the London-based firm Foster & Partners.