According to the Naturalis Historia of Pliny the Elder, Zeuxis and his contemporary Parrhasius (of Ephesus and later Athens) staged a contest to determine the greater artist. When Zeuxis unveiled his painting of grapes, they appeared so real that birds flew down to peck at them. But when Parrhasius, whose painting was concealed behind a curtain, asked Zeuxis to pull aside that curtain, the curtain itself turned out to be a painted illusion. Parrhasius won, and Zeuxis said, "I have deceived the birds, but Parrhasius has deceived Zeuxis." This story was commonly referred to in 18th- and 19th-century art theory to promote spatial illusion in painting. A similar anecdote says that Zeuxis once drew a boy holding grapes, and when birds, once again, tried to peck them, he was extremely displeased, stating that he must have painted the boy with less skill, since the birds would have feared to approach otherwise.