From Roman Athletics: Classical Antecedents to the National Mania
“All at once we saw a bald old man [Trimalchio–Ed.] in a reddish shirt playing at ball with some long-haired boys. It was not the boys that attracted our notice, though they deserved it, but the old gentleman, who was in his house-shoes, busily engaged with a green ball. He never picked it up if it touched the ground. A slave stood near by with a bagful and supplied them to the players. Two eunuchs were standing at different points in the group. One held a silver jordan [wide-necked jar], one counted the balls, not as they flew from hand to hand in the rigour of the game, but when they dropped to the ground” (Petron., Sat. p. 39, Loeb trans.). This game has been identified as trigon, which seems to be depicted on a wall painting in the Baths of Trajan in Rome. Each player was posted at the corner of a triangle. The object was to throw balls back and forth as fast as possible, catching them with one hand and tossing back on e of the other of your opponents with the other.