This square Romanesque tower is a reminder of the days when Prague Castle was protected by massive fortifications and defensive towers. It guarded the eastern entrance to the Castle complex as early as the 12th century. Under Charles IV, its pyramidal roof was covered with gilded lead sheeting and it consequently became known as the Golden Tower. Although it escaped destruction during the great fire that swept through Prague Castle, Malá Strana and Hradčany in June 1541, its masonry was so blackened by smoke that it earned the name the Black Tower. Over the centuries, it served both as the watchman’s quarters and as a debtors’ prison. Today, visitors pass this 26-metre-high tower of pale marlstone when entering Prague Castle via the Old Castle Stairs. It now houses a repository of archaeological finds from Prague Castle and is not open to the public.