Gusle is an very old instrument played all over the Serb lands. Its songs were basic and often the only way to hand down traditions and memory of Serb people during the rule of foreigners. People gathered around gusle players and listened epic songs about Serb heroes and suffering of Serb nation. Very often, large crowd and players began to cry  touched by very emotional contents. It is said that in the year of 1189 grand Serb chieftain Stefan Nemanja saw German Emperor Frederick Barbarossa off from the city of Nis to Third Crusade with the sounds of gusle songs. Montenegrin prince-bishop, greatest Serb poet and father of modern Serb national identity Petar II Petrovic Njegos, in his poem "The Mountain Wreath"  through words of his literature hero Vuk Micunovic said: "In a house where the gusle is not heard, both the house and the people there are dead".

From the Encyclopaedia Britannica

GUSLE - stringed musical instrument of the Balkans, with a round wooden back, a skin belly, and one horsehair string (or, rarely, two) secured at the top of the neck by a rear tuning peg. It is played in a vertical position, with a deeply curved bow. It has no fingerboard, the string being stopped by the sideways pressure of the player's fingers. Gusle players or Guslari are among the few performers continuing the oral tradition of epic poetry. Most of their songs are about the era of Turkish rule and were handed down by teachers or older singers. Because the narratives are orally transmitted, variation in content is inevitable.