- Source
- Polybius. Vols. 1-4. Büttner-Wobst, Theodor, editor. Leipzig: Teubner, 1893.
- Translation
- AI-generated (gemini-3.5-flash) — machine translation; may contain errors
- Languages
- 日本語 · English · 简体中文 · 한국어
- CTS URN
- urn:cts:greekLit:tlg0543.tlg001.humanitext-grc2:9.15.1-9.15.15
- Generated
- Humanitext Reader · reader.humanitext.ai · 2026-11-07
Polybius emphasizes the importance of the right timing in military operations, arguing that a general must understand astronomy—specifically the changes in the length of days and nights, the movement of the zodiac, and the phases of the moon—to measure time accurately.
κρατεῖ δʼ ἐπὶ πάντων μὲν τῶν ἀνθρωπείων ἔργων ὁ καιρός, μάλιστα δὲ τῶν πολεμικῶν.
Opportunity rules over all human undertakings, and most of all those of war.
διὸ προχείρως ἰστέον τῷ στρατηγῷ1 τροπὰς ἡλίου θερινὰς καὶ χειμερινάς, ἔτι δʼ ἰσημερίας καὶ τὰς μεταξὺ τούτων αὐξήσεις καὶ μειώσεις ἡμερῶν καὶ νυκτῶν·
Therefore, the general must have ready at hand knowledge of the summer and winter solstices, and further of the equinoxes, and the increases and decreases of days and nights between them;
οὕτως γὰρ ἂν μόνως δύναιτο συμμετρεῖσθαι πρὸς λόγον τὰ διανύσματα καὶ κατὰ γῆν καὶ κατὰ θάλατταν.
for only in this way could he calculate proportionally the distances to be traversed both by land and by sea.
καὶ μὴν τοὺς κατὰ μέρος καιροὺς ἀναγκαῖον εἰδέναι, καὶ τοὺς τῆς ἡμέρας καὶ τοὺς τῆς νυκτός, πρὸς τὸ γινώσκειν πηνίκα ποιητέον καὶ τὰς ἐξεγέρσεις καὶ τὰς ἀναζυγάς·
Moreover, it is necessary to know the detailed divisions of time, both of the day and of the night, in order to know at what hour one must order both the reveille and the departure;
οὐ γὰρ οἷόν τε τοῦ τέλους τυγχάνειν μὴ οὐ τῆς ἀρχῆς εὐστοχήσαντα.2
for it is not possible to attain the end without having hit upon the right beginning.
τοὺς μὲν οὖν τῆς ἡμέρας καιροὺς τῇ σκιᾷ θεωρεῖν οὐκ ἀδύνατον, ἔτι δὲ τῇ κατὰ τὸν ἥλιον πορείᾳ καὶ τοῖς ἐπὶ τοῦ κόσμου γινομένοις αὐτοῦ τούτου διαστήμασι·
Now, it is not impossible to observe the hours of the day by the shadow, and further by the course of the sun and the intervals of this same body on the celestial sphere;
τοὺς δὲ τῆς νυκτὸς δυσχερές, ἐὰν μή τις ἐπὶ τοῦ φαινομένου τῇ τῶν δώδεκα ζῳδίων οἰκονομίᾳ καὶ τάξει συμπεριφέρηται· πάνυ δὲ καὶ τοῦτο ῥᾴδιον τοῖς τὰ φαινόμενα πεπολυπραγμονηκόσιν.
but those of the night are difficult, unless one is familiar with the arrangement and order of the twelve signs of the zodiac on the celestial sphere; yet this too is very easy for those who have studied the heavenly phenomena.
ἐπεὶ γὰρ ἀνίσων οὐσῶν τῶν νυκτῶν3 ὅμως ἐν πάσῃ τῇ νυκτὶ τῶν δώδεκα ζῳδίων ἓξ ἀναφέρεσθαι συμβαίνει, φανερὸν ὡς ἀναγκαῖον ἐν τοῖς αὐτοῖς μέρεσι πάσης νυκτὸς ἴσα μέρη τῶν δώδεκα ζῳδίων ἀναφέρεσθαι.
For since, though the nights are unequal, it always happens that six of the twelve signs rise in the course of every night, it is clear that in the proportional parts of any night equal parts of the twelve signs must rise.
τοῦ δʼ ἡλίου γνωριζομένου καθʼ ἡμέραν, ποίαν μοῖραν ἐπέχει, δῆλον ὡς δύναντος τούτου4 τὴν κατὰ διάμετρον ἐπιτέλλειν ἀνάγκη.
And since it is known during the day which degree of the zodiac the sun occupies, it is clear that when the sun sets, the point diametrically opposite to it must rise.
λοιπὸν ὅσον ἂν τὸ μετὰ ταύτην μέρος ἀνατεταλκὸς φαίνηται τοῦ ζῳδιακοῦ, τοσοῦτον εἰκὸς ἠνύσθαι τῆς νυκτὸς αἰεί.
Consequently, in proportion as the part of the zodiac rising after this point appears, so much of the night must always be expected to have passed.
γνωριζομένων δὲ τῶν ζῳδίων καὶ κατὰ τὸ πλῆθος καὶ κατὰ τὸ μέγεθος, τοιούτους γίνεσθαι μετὰ ταῦτα συμβαίνει καὶ τοὺς κατὰ μέρος καιροὺς τῆς νυκτός.
And if the signs of the zodiac are known both in number and in size, it follows that the detailed divisions of the night also become known accordingly.
ἐν δὲ ταῖς συννεφέσι νυξὶ τῇ σελήνῃ προσεκτέον, ἐπεὶ διὰ τὸ μέγεθος ὡς ἐπίπαν αἰεὶ τὸ ταύτης ἐμφαίνεται φῶς, καθʼ ὃν ἂν ᾖ τόπον τοῦ κόσμου.
But on cloudy nights, one must attend to the moon, since because of its size its light is almost always visible, in whatever place of the celestial sphere it may be.
καὶ ποτὲ μὲν ἐκ τῶν περὶ τὰς ἀνατολὰς καιρῶν καὶ τόπων στοχαστέον, ποτὲ δὲ πάλιν ἐκ τῶν περὶ τὰς δύσεις, καθυπαρχούσης καὶ περὶ τοῦτο τὸ μέρος ἐννοίας ἐπὶ τοσοῦτον ὥστε συμπεριφέρεσθαι ταῖς καθʼ ἡμέραν διαφοραῖς τῶν ἀνατολῶν.
And sometimes one must calculate from the times and places of its rising, sometimes again from those of its setting, provided that there is already an understanding of this matter sufficient to follow the daily variations of its rising.
ἔστι δὲ τρόπος εὐθεώρητος καὶ περὶ ταύτην· ὅρος γὰρ εἷς μὴν ὡς τύπῳ, καὶ πρὸς αἴσθησιν
And there is an easily observed method concerning this too; for one month is, roughly speaking, a single limit, and to our perception—
- 9.15.2ἰστέον τῷ στρατηγῷ
The verbal adjective ἰστέον (from οἶδα) is used in an impersonal construction with the dative of agent τῷ στρατηγῷ, meaning 'the general must know.'
- 9.15.5μὴ οὐ τῆς ἀρχῆς εὐστοχήσαντα
The double negative μὴ οὐ modifies the conditional participle εὐστοχήσαντα (in the accusative, implying an indefinite subject 'anyone'), meaning 'unless one has hit upon the beginning.'
- 9.15.8ἀνίσων οὐσῶν τῶν νυκτῶν
A genitive absolute construction acting adversatively, translated as 'although the nights are unequal.'
- 9.15.9δύναντος τούτου
A genitive absolute construction where τούτου refers to the sun (ἥλιος) and δύναντος (a variant form of δύνοντος, aorist participle of δύω/δύνω 'to set') means 'when it sets.'
Translated by Gemini 3.5 Flash (published 2026-05-25) · Revision history (1, latest 2026-09-21)
- 2026-09-21 AI review — note 1