Plato, Laws 681a

ὑπωρείαις τρέπονται πρώτας, περιβόλους τε αἱμασιώδεις τινὰς τειχῶν ἐρύματα τῶν θηρίων ἕνεκα ποιοῦνται, μίαν οἰκίαν αὖ κοινὴν καὶ μεγάλην ἀποτελοῦντες. τὸ γοῦν εἰκὸς ταῦθʼ οὕτως γίγνεσθαι. τί δέ; τόδε ἆρα οὐκ εἰκός; τὸ ποῖον; τῶν οἰκήσεων τούτων μειζόνων αὐξανομένων ἐκ τῶν ἐλαττόνων καὶ πρώτων, ἑκάστην τῶν σμικρῶν παρεῖναι κατὰ γένος ἔχουσαν τόν τε πρεσβύτατον ἄρχοντα καὶ αὑτῆς

and make ring-fences of rubble and walls to ward off wild beasts, till finally they have constructed a single large common dwelling. It is certainly probable that such was the course of events. Well, is not this also probable? What? That, while these larger settlements were growing out of the original small ones, each of the small settlements continued to retain, clan by clan, both the rule of the eldest