As stated by Sandy, in northern and central Albania, blood feuds, called gjakmarrja (pronounced Jyak-MARR-Ya, the Albanian term for revenge), is governed by a code of conduct known as the Kanun, or canon in English, of Lek Dukagjini, a 15th century nobleman, or the Code of Lek for short. When a member of a family is slighted, one may seek recompense by injuring the opposing party in a similar manner, all for the sake of preserving one's personal or family honor. One of the few ways to avenge, or pay this "blood debt" is by compensating the family of the deceased, monetarily or otherwise; by securing the forgiveness of the church; or by killing the murderer. Moreover, the Code of Lek, states that women, children and the elderly are not to be targets of "revenge killings".
In the United States the most famous blood feud was the conflict between two American mountain families, the Hatfields and the McCoys. The feud began in 1864, when Confederate soldiers William Anderson "Devil Anse" Hatfield and Jim Vance murdered former Union soldier Asa Harmon McCoy. The Hatfields believed McCoy was responsible for the shooting of a friend of Hatfield's during the war. The feud was fought largely in the 1880s. The Hatfields lived mostly in Logan County in West Virginia, and the McCoys lived mostly across the Tug Fork in adjacent Pike County, Kentucky. The feud ended legally in 1901. Eight Hatfields were jailed for life, and a cousin named Elison Mounts was hanged for murdering McCoys in two separate incidents. More than a dozen were killed from both sides.
Boyd Holbrook's character Clement Mansell sings "We're Going to Be Friends", a song by Jack White and also the theme song to Conan O'Brien's podcast "Conan needs a friend". Conan and Timothy Olyphant are good friends in real life, as he was a guest on his talk show many times.