Crucial documents in the drive to abolish slavery will go on sale next week in New York.
Limited edition original copies of both the Emancipation Proclamation and the 13<sup>th Amendment, both signed by Abraham Lincoln, are expected to fetch more than $5m when they are sold at Sotheby's on May 25.
In the proclamation President Lincoln famously declared that all people held as slaves "henceforward shall be free". It immediately declared 50,000 men, women and children free and was one of the key moments on the way to the famous line from the declaration of independence: "All men are created equal."
According to Sotheby's, the documents were advertised for $10 on 17 June 1864 and sold at the "Great Central fair benefiting the United States Sanitary Commission". This copy is one of only 27 to survive.
It will be sold alongside a copy of the 13<sup>th amendment which officially "abolished slavery and involuntary servitude in the United States". It was the result of 70 years of discussion over the status of slavery.
The copy of the amendment to be sold is one of just 14 signed by Lincoln himself as well as his vice president, the speaker of the house and 36 senators.
Sotheby's said together the documents represented "crucial milestones" in American history and remained pertinent today as the debate over race and immigration was renewed.
Artefacts from Lincoln often attract attention and high prices at auction houses. A copy of Lincoln's speech urging unity amid the civil war sold for $3.4 million in New York in 2009. Last November the final passage of his second inaugural address sold for $2.2 million. Weeks after deliving it, Lincoln was assassinated in a theatre in April 1865.
