Plutarch, Roman Questions 6:
“QUESTION: Why do women kiss their family members on the mouth?
Perhaps, as most think, because it is forbidden for women to drink wine. And so, it was decided that they should kiss their family members, so that they cannot get away with drinking wine, but will be chastised in the company of their household.
Or perhaps it is for the reason which Aristotle has related: it is a much-related story, and said to have been undertaken by the Trojan women in many places, even in Italy. As the men sailed out and got off of their ships, the women burned them in their desire to be done with wandering and the sea. Being afraid of their husbands, they embraced those of their families and households who happened to be there with a kiss and a hug. When their anger had subsided and the men relented, they continued to employ the same affection toward them.
Perhaps, rather, it was a custom given to the women because it have them both honor and power to be seen to have many noble relations and members of the household?
Or perhaps, since it is forbidden to marry one’s relations, affection may only proceed as far as a kiss, and that alone remains as a common symbol of their relation to each other? In earlier times, people did not marry those who were related through blood, and similarly so, people do not marry their aunts or their sisters, but much later they proceeded to marry cousins for this reason: a man in need of money, but noble in all other respects, and more well-loved by the people than the other bigshots in the city, seemed to have married his heiress cousin and to be getting rich off of her. When a charge was leveled against him for this, the people dismissed the charge and did not even compel him to defend himself against it, voting that everyone should be permitted to marry up to their cousins, but should be prevented from marrying any farther into their relations than that.”
‘Διὰ τί τοὺς συγγενεῖς τῷ στόματι φιλοῦσιν αἱ γυναῖκες;’ πότερον, ὡς οἱ πλεῖστοι νομίζουσιν, ἀπειρημένον ἦν πίνειν οἶνον ταῖς γυναιξίν· ὅπως οὖν αἱ πιοῦσαι μὴ λανθάνωσιν ἀλλ’ ἐλέγχωνται περιτυγχάνουσαι τοῖς οἰκείοις, ἐνομίσθη καταφιλεῖν;
ἢ δι’ ἣν ᾿Αριστοτέλης (fr. 609) ὁ φιλόσοφος αἰτίαν ἱστόρηκε; τὸ γὰρ πολυθρύλλητον ἐκεῖνο καὶ πολλαχοῦ γενέσθαι λεγόμενον ὡς ἔοικεν ἐτολμήθη καὶ ταῖς Τρῳάσι περὶ τὴν ᾿Ιταλίαν. τῶν γὰρ ἀνδρῶν, ὡς προσέπλευσαν, ἀποβάντων ἐνέπρησαν τὰ πλοῖα, πάντως ἀπαλλαγῆναι τῆς πλάνης δεόμεναι καὶ τῆς θαλάττης· φοβηθεῖσαι δὲ τοὺς ἄνδρας ἠσπάζοντο τῶν συγγενῶν καὶ οἰκείων μετὰ τοῦ καταφιλεῖν καὶ περιπλέκεσθαι τοὺς προστυγχάνοντας. παυσαμένων δὲ τῆς ὀργῆς καὶ διαλλαγέντων ἐχρῶντο καὶ τὸ λοιπὸν ταύτῃ τῇ φιλοφροσύνῃ πρὸς αὐτούς.
ἢ μᾶλλον ἐδόθη τοῦτο ταῖς γυναιξὶν ὡς τιμὴν ἅμα καὶ δύναμιν αὐταῖς φέρον, εἰ φαίνοιντο πολλοὺς καὶ ἀγαθοὺς ἔχουσαι συγγενεῖς καὶ οἰκείους;
ἤ, μὴ νενομισμένου συγγενίδας γαμεῖν, ἄχρι φιλήματος ἡ φιλοφροσύνη προῆλθεν καὶ τοῦτο μόνον ἀπελείφθη σύμβολον καὶ κοινώνημα τῆς συγγενείας; πρότερον γὰρ οὐκ ἐγάμουν τὰς ἀφ’ αἵματος, ὥσπερ οὐδὲ νῦν τιτθίδας οὐδ’ ἀδελφὰς γαμοῦσιν, ἀλλ’ ὀψὲ συνεχώρησαν ἀνεψιαῖς συνοικεῖν ἐκ τοιαύτης αἰτίας· ἀνὴρ χρημάτων ἐνδεὴς τὰ δ’ ἄλλα χρηστὸς καὶ παρ’ ὁντινοῦν τῷ δήμῳ τῶν πολιτευομένων ἀρέσκων ἐπίκληρον ἀνεψιὰν ἔχειν ἔδοξε καὶ πλουτεῖν ἀπ’ αὐτῆς· ἐπὶ τούτῳ δὲ γενομένης αὐτοῦ κατηγορίας ὁ δῆμος ἀφεὶς τὴν αἰτίαν ἐλέγχειν ἔλυσε τὸ ἔγκλημα, ψηφισάμενος πᾶσιν ἐξεῖναι γαμεῖν ἄχρις ἀνεψιῶν, τὰ δ’ ἀνωτέρω κεκωλῦσθαι.