Second Fortification of Salzburg:
The second fortification of Salzburg ("Zweite Stadtbefestigung") was funded by the burghers of Salzburg. It was built in a construction campaign between 1465 and 1480 and included several large gates, which partly took advantage of previously existing structures from the first fortification series: The Äußeres Nonnbertor, Äußeres Nonntaltor, Kumpfmühltor, Gate at the old Synagogue/Hellbräu, Klampferertor, Rathausbogen gate, Löchlbogen, Sternbräubogen, Inneres Gstättentor, Bürgerwehr, extensive walls on the right side of the Salzach, Äußeres Lederertor, Hexenturm tower and Äußeres Steintor at Bürglstein.
For following years, construction work on other gates is recorded: Mülleggertor (1514, rebuilt in 1605); Klausentor (rebuilt in 1612 after a fire); Linzertor (extension in 1596; rebuilt in 1614); Bergstrasstor (rebuilt in 1615); Gstättentor (rebuilt or modernised in 1618).
Note that this indicates a rather active period in which a lot of construction took place. This is largely due to the wealth that Salzburg accumulated in the late Middle Ages. The reign of Prince Archbishop Leonard von Keutschach between 1495 and 1519 was characterised by intensive re-modelling of the Festung Hohensalzburg. Under his supervision, it became the powerful castle that we see today - at least when we are standing inside. The outer parts, such as the bastions around it and the gates on the way to it were built in the 17th century.
City Walls on the SalzburgWiki (German)