E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
White Widow.
The Duchess of Tyrconnel, wife of Richard Talbot, Lord-deputy of Ireland under James II., created Duke of Tyrconnel a little before the king’s abdication. After the death of Talbot, a female, supposed to be his duchess, supported herself for a few days by her needle. She wore a white mask, and dressed in white. (Pennant: London, p. 147.)
