was of pure gold, and rendered the wearer invulnerable. It was taken possession of by Rinaldo (Orlando Furioso). Cervantes tells us of a barber who was caught in a shower, and to protect his hat clapped his brazen basin on his head. Don Quixote insisted that this basin was the enchanted helmet of the Moorish king.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894