Only Unity Saves the Serb (Serbian: Само слога Србина спасава/Samo sloga Srbina spasava, "only unity saves the Serb") is a popular motto and slogan in Serbia and among Serbs, often used as a rallying call against foreign domination and during times of national crisis. The phrase is an interpretation of what is taken to be four Cyrillic letters for "S" (written С) on the Serbian cross, itself originally a Byzantine symbol. Popular tradition attributes the motto to Saint Sava, the founder of the Serbian Orthodox Church.
The Serbian cross is based on the Palaiologos symbol, a cross with four β for the motto "King of Kings, Ruling Over Kings" (Basileus Basileōn, Basileuōn Basileuontōn). In the Middle Ages, both the "Greek style", with closed fire-steels (β - B), and the "Serbian syle", with open fire-steels (C - S), were used in Serbia. It has been argued that the Serbian cross was used as a national symbol already in the 14th century. The symbol was used in the Illyrian Armorials for Serbia. The Serbian cross reappeared during the First Serbian Uprising against the Ottoman Empire, from 1804 to 1813, and has since been used in state insignia. It served as a reference to the medieval Serbian Empire and professed the part which Serbs played in defending Christendom against the Ottoman Empire in the 14th century.
According to legend, the origin of the C-shaped Serbian cross lies with Saint Sava, the first Archbishop of the Serbian Church and the patron saint of Serbs, who based his design on the Byzantine original. The phrase "Only Unity Saves the Serbs" is traditionally attributed to him. He is said to have uttered it to urge the Serbian people to declare national autonomy and resist domination by the Roman Catholic Church.