Thus Athenæus (Bk. xiii, Ch. XX) says: "In the Island of Chios it is a beautiful sight to go to the gymnasia and the race-courses, and to see the young men wrestling naked with the maidens who are also naked."
Augustine (De civitate Dei, lib. ii, cap. XIII) refers to the same point, contrasting the Romans with the Greeks who honored their actors.
See "The Evolution of Modesty" in the first volume of these Studies, where this question of the relationship of nakedness to modesty is fully discussed.