Ἰστέον, ὅτι ὁ Μοραβίας ἄρχων, ὁ Σφενδοπλόκος, ἀνδρεῖος καὶ φοβερὸς εἰς τὰ πλησιάζοντα αὐτῷ ἔθνη γέγονεν. ἔσχε δὲ ὁ αὐτὸς Σφενδοπλόκος τρεῖς υἱούς, καὶ τελευτῶν διεῖλεν εἰς τρία μέρη τὴν ἑαυτοῦ χώραν, καὶ τοῖς τρισὶν υἱοῖς αὐτοῦ ἀνὰ μιᾶς μερίδος κατέλιπεν, τὸν πρῶτον καταλείψας ἄρχοντα μέγαν, τοὺς δὲ ἑτέρους δύο τοῦ εἶναι ὑπὸ τὸν λόγον τοῦ πρώτου υἱοῦ. παρῄνεσεν δὲ αὐτοὺς τοῦ μὴ εἰς διάστασιν καὶ κατ’ ἀλλήλων γενέσθαι, παράδειγμα αὐτοῖς τοιοῦτον ὑποδείξας· ῥάβδους γὰρ τρεῖς ἐνεγκὼν καὶ συνδήσας, δέδωκεν τῷ πρώτῳ υἱῷ τοῦ ταύτας κλάσαι, τοῦ δὲ μὴ ἰσχύσαντος, πάλιν δέδωκεν τῷ δευτέρῳ, ὡσαύτως καὶ τῷ τρίτῳ, καὶ εἶθ’ οὕτως διαιρῶν τὰς τρεῖς ῥάβδους δέδωκεν τοῖς τρισὶ πρὸς μίαν· οἱ δὲ λαβόντες καὶ κελευσθέντες ταύτας κλάσαι, εὐθέως αὐτὰς κατέκλασαν. καὶ διὰ τοιούτου ὑποδείγματος παρῄνεσεν αὐτοὺς εἰπών, ὡς ὅτι· “εἰ μὲν διαμένετε ἐν ὁμοψυχίᾳ καὶ ἀγάπῃ ἀδιαίρετοι, ἀκαταγώνιστοι παρὰ τῶν ἐναντίων καὶ ἀνάλωτοι γενήσεσθε· εἰ δὲ ἐν ὑμῖν γένηται ἔρις καὶ φιλονικία, καὶ διαχωρισθῆτε εἰς τρεῖς ἀρχάς, μὴ ὑποκείμενοι τῷ πρώτῳ ἀδελφῷ, καὶ ὑπ’ ἀλλήλων ἀφανισθήσεσθε, καὶ ὑπὸ τῶν πλησιαζόντων ὑμῖν ἐχθρῶν παντελῶς ἐξολοθρευθήσεσθε.”
(Constantine Porphyrogenitus, De Administrando Imperio 41)

The prince of Moravia, Sphendoplokos, was valiant and terrible to the nations that were his neighbors. This same Sphendoplokos had three sons, and when he was dying he divided his country into three parts and left a share apiece to his three sons, leaving the eldest to be great prince and the other two to be under the command of the eldest son. He exhorted them not to fall out with one another, giving them this example by way of illustration: he brought three wands and bound them together and gave them to the first son to break them, and when he was not strong enough, handed them on to the second, and in like manner to the third, and then separated the three wands and gave one each to the three of them; when they had taken them and were bidden to break them, they broke them through at once. By means of this illustration he exhorted them and said: “If you remain undivided in concord and love, you shall be unconquered by your adversaries and invincible; but if strife and rivalry come among you and you divide yourselves into three governments, not subject to the eldest brother, you shall be both destroyed by one another and brought to utter ruin by the enemies who are your neighbors.” (tr. Romilly James Heald Jenkins)