Abraham Lincoln was the 16th President of the United States of America and a member of the Republican Party. He was assassinated by a Confederate supporter of the slavery on the 15th April 1865. The historiography and the world public opinion consider him one of the most important and popular Presidents of the United States. He abolished slavery and preserved the national federal unity, defeating the Confederate States in the American Civil War. On the occasion of the 150th anniversary of Lincoln’s death, the Republic of San Marino pays homage to his figure and to the ancient friendly relationships with a 10 Euro silver proof coin. On the reverse of the coin, the British designer Matt Dent reports the words “Great and Good Friends”. This quotation is the beginning of President Lincoln’s message to the Captains Regent, on the occasion of the acknowledgement of the honorary citizenship of the Republic of San Marino, on the 7th May 1861. The President wrote that although the dominion of San Marino was small, the Republic was nevertheless one of the most honored in all history. Lincoln added that San Marino had by its experience demonstrated the truth and encouraged the friendship among people; the Government, founded on Republican principles, was administered therefore in a secure and enduring way.