Passage 3.11.2
Λακεδαιμονίων τοῖς Σπάρτην ἔχουσίν ἐστιν ἀγορὰ θέας ἀξία, καὶ τῆς τε γερουσίας βουλευτήριον καὶ τῶν ἐφόρων καὶ νομοφυλάκων καὶ καλουμένων Βιδιαίων ἀρχεῖά ἐστιν ἐπὶ τῆς ἀγορᾶς. ἡ μὲν δὴ γερουσία συνέδριον Λακεδαιμονίοις κυριώτατον τῆς πολιτείας, οἱ λοιποὶ δέ εἰσιν ἄρχοντες· τοῖς δὲ ἐφόροις καὶ Βιδιαίοις πέντε ἀριθμὸν ἑκατέροις οὖσι, τοῖς μὲν τοὺς ἐπὶ τῷ Πλατανιστᾷ καλουμένῳ καὶ ἄλλους τῶν ἐφήβων ἀγῶνας τιθέναι καθέστηκεν, ἔφοροι δὲ τά τε ἄλλα διοικοῦσι τὰ σπουδῆς μάλιστα ἄξια καὶ παρέχονται τὸν ἐπώνυμον, καθὰ δὴ καὶ Ἀθηναίοις τῶν καλουμένων ἐννέα ἐπώνυμός ἐστιν εἷς ἄρχων.
The marketplace of the Lacedaemonians who occupy Sparta is worthy of seeing, and situated upon it are the council-house of the Gerousia, as well as the offices of the Ephors, the Nomophylakes ("Guardians of the Laws"), and the so-called Bidiaeans. The Gerousia is indeed, most authoritative in the constitution for the Lacedaemonians, while the others serve as magistrates. As for the Ephors and the Bidiaeans, each body consists of five men respectively; the latter are appointed to oversee the contests held at the place called Platanistas and other competitions among the young men, while the Ephors manage all the most important public affairs and give their name to the year, just as among the Athenians there is one distinguished archon who lends his name to the year from among the so-called nine archons.