As far as historical treasures go, this is a big one.
Found in the basement of an elderly descendant of Andrew Haswell Green -- the man President Theodore Roosevelt once dubbed "the father of greater New York" -- thousands of items, including many of national significance, are seeing the light of day for the first time in more than a century.
"Frankly, the whole thing is very overwhelming," said Bill Ralph, a freelance historian hired to catalog and research the Green finding. "I've always kind of thought of it as a time capsule of 250 years."
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From a rare copy of George Washington's will and the original letters of 18th and 19th century presidents to dozens of haute couture dresses and century-old Tiffany silver, the collection is expected to fetch more than $1 million at a four-day auction that ends Sunday.
"This is an unprecedented group of things," said auctioneer Richard Oliver, president of the Maine-based R.W. Oliver's, which is handling the auction.
Most of the items hadn't been touched since shortly after Green's murder in 1903. Boxed up and passed down from descendant to descendant, they wound up in the Kennebunk, Maine, basement of Julia Green, a distant niece.
Green, unmarried and childless, died in 2009 and left her possessions to her niece and nephew, Lisa Buchanan, 51, and John Green, 54.
"It was, 'Oh, my God,'" John Green said of the moment they realized the scope of what was actually in the hundreds of boxes. "We were dumbfounded, to say the least."
John Green, who lives in Kennebunk, and Buchanan, of Denver, Colo., said they and their aunt always knew they probably had thousands of items of significance to the family and its history, but had no idea they were in possession of anything that could be considered a national treasure.
"My aunt had kind of squirreled it all away," Buchanan said.
But once the siblings were put in charge, they decided they wanted their great-great-great uncle's collection to go to "people who had a stake in history."
"I want these things to be in the right hands, whether it's the Smithsonian or some private collector; people who appreciate this," Buchanan said. "People who are responsible."
Auctioneer Oliver said he's expecting patrons to the auction from schools across the country, as well as noted museums and private individuals.
One irony, historian Ralph noted, is that Julia Green's father, the previous keeper of the collection, wrote his daughter that he had tried unsuccessfully around 1947 to give some of the items to Yale University and and the New York Historical Society.
"He said, "I have an enormous pile of trash here that might be of interest to you.' Luckily they declined," Ralph said. "He didn't fully know what was there."
The proceeds of the auction will go to John Green and Buchanan. But because the collection is so vast and neither of them made it through ever single item, John Green said he's prepared to place a few bids himself.
He said he's interested in a few antique doorstops and a map of the Kennebunk seashore in the 1800s. His wife, he said, is interested in the Tiffany silver.