The 1861 letter was written personally by President Lincoln

A letter written by former US President Abraham Lincoln to a schoolboy nearly 150 years ago is to go on sale for $60,000 (£36,000) in Philadelphia.

George Patten was with his journalist father when both met the commander-in-chief.

The 16th US president wrote in 1861 after the eight-year-old was mocked by his disbelieving classmates.

The handwritten, signed note confirms the pair met and was sent two weeks after the Lincoln's inauguration.

The letter reads: "Whom it may concern, I did see and talk with master George Evans Patten, last May, at Springfield, Illinois. Respectfully, A Lincoln."

Lincoln put pen to paper after the boy's teacher wrote to him.

Nathan Raab, vice-president of the Raab Collection, which is selling the letter, said there were no other known surviving letters written by Lincoln to a child.

This year, a number of events have been held across the US to mark the bicentenary of the former president's birth.