The more than 900-year-old citadel dates back to the investiture controversy between emperor and pope over the right to appoint the bishop. As a faithful servant of the pope, Archbishop Gebhart von Salzburg had the strongholds of Hohensalzburg, Hohenwerfen and Friesach built on his sovereign territory in 1077. Expansion of Gebhart's fortifications were temporarily completed under Konrad I (1160 - 1147).
During its long history the Hohensalzburg Fortress has always remained unconquered by enemy troops.
Source i.a. www.salzburg.info