NEW YORK - The petition was signed by 195 children in Concord, Mass. Their single request was painfully simple: that the president free "all the little slave children in this country."

On April 5, 1864, Abraham Lincoln replied to the woman who had organized the petition, ending his letter, "While I have not the power to grant all they ask, I trust they will remember that God has, and that, as it seems, He wills to do it."

Lincoln's letter is the centerpiece of an extraordinarily rich collection of historic American manuscripts, including some 20 rare Lincoln items, that will be auctioned off this week in a sale that could yield at least $7.9 million for the New York doctor who acquired the documents over the course of a 23-year collecting career.

"This is a very moving piece because Lincoln was a lawyer and he parsed the issue of slavery very closely," said Selby Kiffer, a manuscript specialist at Sotheby's New York branch, where the collection went on display last week. "So even though he abhorred slavery, he didn't feel he had the right to end slavery. But he gives this very personal and fatherly reply in which he says he's willing to be God's instrument."

The auction house estimates that the original letter, which became well known after it was widely reprinted during the Civil War, will sell for $3 million to $5 million and is likely to become the most expensive Lincoln manuscript ever sold.

Among other highlights in the 111 lots that will be sold Thursday are three pages of autographs, including Lincoln's, gathered at Gettysburg on Nov. 19, 1863, the only known Lincoln autograph from the day he delivered the Gettysburg Address. Thomas Jefferson tells a correspondent in 1790 that he has decided to accept George Washington's offer to become the first Secretary of State of the young country.

A land deed signed by Meriwether Lewis and William Clark is a rare example of a document bearing the signatures of both explorers. An 1831 letter written by former President John Quincy Adams lays out the divisions between North and South and seems to foretell the bloody conflict that broke out 30 years later.

And, writing from prison two weeks before his execution in November 1859, the anti-slave agitator John Brown contemplated his end in a densely written, heavily underlined three-page letter.

"As to both the time and manner of my death, I have but very little trouble on that score," Brown wrote to a Connecticut minister who had been his teacher. "Farewell till we `meet again.'"

Dr. Robert Small, the owner of the collection, said his aim in seeking out historic documents was not simply to amass autographs but to find items in which famous figures revealed something of themselves.

"American history, a sense of American history, always overwhelmed me," said Small, 54, a Manhattan internist who is selling the collection after retiring from his practice. "I admired the establishment of our government, how we formed as a democracy and retained our democracy. It's amazing how this country has stuck together and abided by the Constitution."

Small started collecting in 1985, when he made a house call on a woman who could trace her ancestors back to the American Revolution. On her wall hung an elegantly engraved certificate for the Society of the Cincinnati, a fraternal order of officers who had served in the Continental Army. It was signed "G. Washington."

"I was fascinated to see that," Small said. "I had never seen a signature of George Washington, and never knew that they existed in private hands."

He persuaded the woman to sell it to him, and that established what became a customary practice as he built his collection. Instead of buying mainly from manuscript dealers, he developed what he called a "collection of collectors," a network of people who alerted him to items at estate sales or out-of-the-way locations.

Small also scoured the catalogs of small auctions. That's where he found a single leaf, written on front and back, from George Washington's diary - the only two pages of the diary in private hands.

Among the items up for sale - which represents nearly all of Small's collection - are letters or documents signed by 26 presidents, letters or autographed items by such figures as Robert E. Lee, Thomas Edison, Gen. George S. Patton, and Major John Andre, the British spy during the Revolution, whose letter to his mother reveling in his good fortune dates from less than a month before he was captured behind American lines and later hanged.

"Bob had a real nose for items with a personal aspect of the writer's character, or that captured the critical issues of the day," said Kiffer. "These aren't simply letters sending out an autograph or declining a dinner invitation."

Unlike most of his collection, Small bought Lincoln's reply to the children's petition from a dealer, but he declined to say how much he paid for it.

The children's petition had been organized by Mary Mann, the widow of educator Horace Mann and a determined abolitionist. Lincoln expert Harold Holzer believes that Lincoln intended his response to be widely circulated. He wrote a draft, which is among the Lincoln papers in the Library of Congress, before carefully copying out the text on a fresh sheet of stationery, which is headed "Executive Mansion."

"We know he had this affinity for children, and apparently he was very moved by the petition," said Holzer, whose many Lincoln books includes "Dear Mr. Lincoln: Letters to the President." "He wanted to be the paterfamilias to the nation. He had great sympathy for what the children were saying, yes, but also a really smart sense of public relations. Why else would he write it over, on one page, so it could be engraved?"

With the Emancipation Proclamation, Lincoln had used his authority as commander-in-chief to order that slaves in Confederate states be freed. But he maintained that the presidency did not give him the power to abolish slavery. That could only be done by amending the constitution.

Such a move was already afoot. Three days after he wrote to Mary Mann, the Senate approved the 13th amendment, formally ending slavery. The amendment was ratified by the states in December 1865.

David Redden, the head of Sotheby's books and manuscripts division, calls the Small collection the most important group of Lincoln letters to come up for auction since the 1978-1981 sale of the Lincoln collection owned by Chicagoans Philip and Elsie Sang.

The current record-holder among Lincoln manuscripts is a speech in Lincoln's handwriting that sold for $3.1 million in 2002.

If the letter to Mary Mann surpasses that, it's unlikely the buyer will be a museum or historic society, which generally cannot afford such items. The letter and other high-priced items are likely to go to another private collector, Small said.

David Blanchette, spokesman for the Abraham Lincoln Presidential Library and Museum in Springfield, said the library's foundation, which buys items for the collection, does not have funds to bid on the most valuable Lincoln documents because it is still paying for the Louise Taper collection of more than 1,500 Lincoln artifacts that it bought last year.

(c) 2008, Chicago Tribune.

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