Letters 88.40

Apion, the scholar, who drew crowds to his lectures all over Greece in the days of Gaius Caesar and was acclaimed a Homerid by every state, used to maintain that Homer, when he had finished his two poems, the Iliad and the Odyssey, added a preliminary poem to his work, wherein he embraced the whole Trojan war. The argument which Apion adduced to prove this statement was that Homer had purposely inserted in the opening line two letters which contained a key to the number of his books.

Seneca, Letters to Lucilius 88.40, translated by Richard Mott Gummere