Thaïs (painting)  Thaïs is a portrait by Sir Joshua Reynolds of the English courtesan Emily Warren in the guise of the "hetaera" Thaïs, mistress of Alexander the Great. It is in oil on canvas and measures 229 x 145 cm. She holds a burning torch and with the other hand exhorts Alexander and his followers to burn down Persepolis. Reynolds exhibited it at the Royal Academy in London in 1781. It is now at Waddesdon Manor. The painting was published as a print engraved by Franscesco Bartolozzi in 1792.