The masks of the Old Comedy fall into two classes, those for real characters, and those for fictitious ones. When real individuals were introduced upon the stage, such as Socrates and Euripides, the masks were portraits of the actual persons. Before a word was spoken the character was recognized by the audience. When Aristophanes brought out the Knights, the general terror inspired by Cleon was so great, that the mask-makers refused to make a portrait-mask of him, and an ordinary mask had to be worn. Socrates, during the performance of the Clouds, is said to have stood up in his place in the theatre, to enable the strangers present to identify him with the character upon the stage.[771] The fictitious masks, as we learn from the grammarians, were grotesque and extravagant in type.[772] They are represented as such in the works of art. The mouth is large and wide open, and the features twisted into a grimace. At the same time the masks in the Attic representations are less distorted and unnatural than those of the Phlyakes vases. The expression on the masks is mostly of a cheerful and festive kind; but sometimes crafty, thoughtful, or angry features are portrayed. Not infrequently in the Old Comedy figures of a fanciful and absurd character were introduced upon the stage. Thus Pseudartabas, the King’s Eye, had a mask with one huge eye in the centre of it. The trochilus in the Birds created laughter by its immense beak. The epops was provided with a ridiculously long crest, but seems otherwise to have been dressed like a human figure. Iris in the Birds came on the stage with outspread wings, swelling tunic, and a head-covering of enormous size, so as to cause Peisthetaerus to ask her whether she was a ship or a hat. Prometheus, with his umbrella, and Lamachus with his nodding crests, are further examples of grotesque costume.[773] The covering for the feet was not, as in the later comedy, of one conventional type, but varied according to the sex and position of the character. Several kinds of boot and shoe are referred to in Aristophanes.[774]