Plato, Laws 850b

βουλομένῳ καὶ δυναμένῳ κατοικεῖν, τέχνην κεκτημένῳ καὶ ἐπιδημοῦντι μὴ πλέον ἐτῶν εἴκοσιν ἀφʼ ἧς ἂν γράψηται, μετοίκιον μηδὲ σμικρὸν τελοῦντι πλὴν τοῦ σωφρονεῖν, μηδὲ ἄλλο αὖ τέλος ἕνεκά τινος ὠνῆς ἢ καὶ πράσεως· ὅταν δʼ ἐξήκωσιν οἱ χρόνοι, τὴν αὑτοῦ λαβόντα οὐσίαν ἀπιέναι. ἐὰν δʼ ἐν τοῖς ἔτεσι τούτοις αὐτῷ συμβῇ λόγου ἀξίῳ πρὸς εὐεργεσίαν τῆς πόλεως γεγονέναι τινὰ ἱκανήν, καὶ πιστεύῃ πείσειν βουλὴν καὶ ἐκκλησίαν, ἤ τινα ἀναβολὴν τῆς ἐξοικήσεως

provided that he has a craft and remains in the country not more than twenty years from the date of his registration, without the payment of even a small aliens’ tax, except virtuous conduct, or indeed any other tax for any buying or selling; and when his time has expired, he shall depart, taking with him his own property. And if within the period of twenty years it should happen that he has proved his merit by doing some signal service to the State, and if he believes that he can persuade the Council and Assembly to grant his request and authorize a