The sword of Edward the Confessor, which, having no point, was the emblem of mercy. The royal sword of England was so called to the reign of Henry III.
But when Curtana will not do the deed, You lay the pointless clergy-weapon by, And to the laws, your sword of justice, fly.
Dryden: Hind and Panther, part ii. 419-21.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894