(Bloomberg) -- Hundreds of artworks from the collection of late art dealer Ginny Williams, estimated at more than $50 million, are heading to Sotheby’s.

Works by women, including postwar masters Lee Krasner and Joan Mitchell, comprise the bulk of the 450-piece trove, and the top lots will be offered in a standalone live sale on June 29 in New York, Sotheby’s said Friday. The company’s traditional evening sale of contemporary art, which had been postponed from this month, will immediately follow.

Sotheby’s said it has already secured more than $175 million of art for the planned live sales. It will be the first public test of the high-end art market since the coronavirus pandemic put the art world on lockdown in March. Christie’s upended the traditional format with a relay-style auction in four global cities on July 10.

In coming days, Sotheby’s will provide more details about how it plans to conduct its live auctions and previews. Christie’s said it will stream its live auctions online and follow government-mandated social-distancing guidelines.

Williams, who died last year, was a pioneering collector-turned-dealer based in Denver. She served on the boards of the Solomon R. Guggenheim Museum and the Hirshhorn Museum & Sculpture Garden in Washington. She was friend with many of the female artists whose works she collected.

The top lot of the Williams collection at Sotheby’s is a 9-foot-tall canvas by Mitchell, “Straw” (1976), estimated at $5 million to $7 million. Krasner’s “Re-Echo” (1957), is expected to sell for $4 million to $6 million. Helen Frankenthaler’s “Royal Fireworks” (1975) -- about 15-feet-wide -- may fetch $2 million to $3 million.

Williams was an avid photographer, having studied with Austrian-American photojournalist Ernst Haas. Her collection started with photographs and eventually expanded to abstract art.

Photographs from the collection, including those by Diane Arbus and Dorothea Lange, will be offered in a separate sale on July 14, Sotheby’s said.

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