I’m overlooking Plutarch (Boeotia c. 46 – c. 120 AD) who lived much later than Xenophon (Athens c. 430 – c. 350 BC).
Xenophon writes in Constitution of the Lacedaimonians:
I think I ought to say something also about intimacy with boys, since this matter also has a bearing on education. In other Greek states, for instance among the Boeotians, man and boy live together, like married people; elsewhere, among the Eleians, for example, consent is won by means of favours. Some, on the other hand, entirely forbid suitors to talk with boys.
The customs instituted by Lycurgus were opposed to all of these. If someone, being himself an honest man, admired a boy’s soul and tried to make of him an ideal friend without reproach and to associate with him, he approved, and believed in the excellence of this kind of training. But if it was clear that the attraction lay in the boy’s outward beauty, he banned the connexion as an abomination; and thus he caused lovers to abstain from boys no less than parents abstain from sexual intercourse with their children and brothers and sisters with each other.