Book 12: The Sirens; Scylla and Charybdis
why was he intelligent?
He was intelligent because he had to chose between two paths " one of two courses you may take, and you yourself must weigh them." Lady Circe said. The first path would be no surviors. The second path was Scylla. He chose Scylla becuase he would only lose at least 6 of his men rather than all.