A key part of the medieval fortress, the Broad Arrow Tower was originally used as a guard tower. From it, soldiers could cover the approaches to the east curtain wall with their crossbows. Today it contains an interactive exhibition in which visitors are able to discover how, together, the building and its soldiers were a formidable war machine. 

From the 14th century, the Broad Arrow Tower was connected with the Wardrobe, the government department responsible for royal supplies. 
From Henry VIII’s reign, it was linked to the nearby Wardrobe Tower by a long storehouse, now demolished.  As part of the Great Wardrobe, royal robes and valuable furnishings were kept here. 

In later years, the tower became a prison and contains many inscriptions from prisoners that were held here in the 16th and 17th centuries.