A letter written by former US President Abraham Lincoln has sold for $3.4m (£1.7m) at auction in New York, setting a record for any American manuscript.
The 1864 reply to a petition by 195 children asking for the freedom of "all the slave children in this country" surpassed the previous record of $3.1m.
It was bought by an American collector bidding by telephone, Sotheby's said.
The letter was the highlight of a sale of some 100 manuscripts written by other American historical figures.
Other highlights included documents written by George Washington, a Lincoln autograph penned on the day of his famous Gettysburg Address, and one from the sixth US president, John Quincy Adams, foretelling the Civil War.
Sotheby's said the record-breaking manuscript was "arguably Lincoln's most personal and powerful statement on God, slavery and emancipation".
The letter, dated 5 April 1864, is a response to some 195 boys and girls who put their names to a document entitled "Children's petition to the president asking him to free all the little slave children in this country."
"Please tell these little people," Lincoln wrote, "I am very glad their young hearts are so full of just and generous sympathy, and that while I have not the power to grant all they ask, I trust that they will remember that God has, and that, as it seems, He wills to do it."
In 1862 and 1863, Lincoln signed two executive orders known as the Emancipation Proclamation, which freed all slaves in areas still held in some Confederate states.
But not all of them were freed until 1865, when the US constitution's 13th Amendment formally abolished slavery. Lincoln was assassinated earlier that year.
The previous record price for a Lincoln manuscript, $3.1m (£1.55m), was for a speech outlining his plans for post-Civil War reconstruction.