(2 syl.). An Athenian courtesan who induced Alexander, when excited with wine, to set fire to the palace of the Persian kings at Persepolis.
The king seized a flambeau with zeal to destroy; Tha is led the way to light him to his prey, And, like another Helen, flred another Troy.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Thais from Infoplease: