The German emperor Frederick I Barbarossa, one of the greatest emperors of his time in Western Europe, stayed in Belgrade when leading a large army to the crusades. He arrived in Belgrade at the end of June 1189, where he, his men, and his escort celebrated festivals of the apostles Peter and Paul. The German emperor entered the city, discovering it to be greatly different from what the soldiers during the Second Crusade had seen. At the time of Barbarossa’s stay, Belgrade was a half-destroyed Byzantine town. The town was in very poor condition and was never restored again during the Byzantium period.
J.Kalić Mijušković, Belgrade in the Middle Ages, Belgrade, 1967 (A bit of my country’s history. More to come.)