Feuds begin because one party perceives itself to have been attacked, insulted or wronged by another. Intense feelings of resentment trigger the initial retribution, which causes the party to feel equally aggrieved. The dispute is subsequently fuelled by a cycle of retaliatory violence. This continual cycle of provocation and retaliation makes it difficult to end the feud peacefully. Feuds frequently involve the original family members and/or associates, can last for generations. They can be interpreted as an outgrowth of social relations based in family honor. Until the early period, feuds were considered legitimate legal instruments and were regulated to some degree. For example, Serb culture calls this krvna osveta, meaning blood revenge, in the English-speaking world, vendetta is sometimes extended to mean any other long-standing feud, not necessarily involving bloodshed. Sometimes, it is not mutual, but rather refers to a series of hostile acts waged by one person against another without reciprocation. Blood feuds were common in societies with a rule of law. An entire family is considered responsible for any one of them has done. Sometimes two separate branches of the family have even come to blows, or worse, over some dispute. The practice has mostly disappeared with more centralized societies where law enforcement, in Homeric ancient Greece, the practice of personal vengeance against wrongdoers was considered natural and customary, Embedded in the Greek morality of retaliation is the right of vengeance. Feud is a war, just as war is a series of revenges. In the ancient Hebraic context, it was considered the duty of the individual, the executor of the law of blood-revenge who personally put the initial killer to death was given a special designation, goel haddam, the blood-avenger or blood-redeemer. Six Cities of Refuge were established to provide protection and due process for any unintentional manslayers, the avenger was forbidden from harming the unintentional killer if the killer took refuge in one of these cities. According to historian Marc Bloch, The Middle Ages, from beginning to end, the onus, of course, lay above all on the wronged individual, vengeance was imposed on him as the most sacred of duties. The solitary individual, however, could do but little, moreover, it was most commonly a death that had to be avenged
Ponte dei Pugni ("Bridge of Fists") in Venice was used by rival clans to stage fist fights
Vatheia, a typical Maniot village famous for its towers
The defensive towers built by feuding clans of Svaneti, in the Caucasus mountains
A fortified tower used as refuge for men involved in a blood feud who are vulnerable to attack. Thethi, northern Albania.