E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Bold as Beauchamp (Beech-um). It is said that Thomas Beauchamp, Earl of Warwick, with one squire and six archers, overthrew 100 armed men at Hogges, in Normandy, in 1346.
This exploit is not more incredible than that attributed to Captal-de-Buch, who, with forty followers, cleared Meaux of the insurgents called La Jacquerie, 7,000 of whom were slain by this little band, or trampled to death in the narrow streets as they fled panic-struck (1358).
Bold as brass. Downright impudent; without modesty. Similarly, we say brazen-faced.
I make bold to say. I take the liberty of saying; I venture to say.