Laudator Temporis Acti

Herodotus 6.27.3 (tr. A.D. Godley):

Then the sea-fight broke upon them and beat the city to its knees.

μετὰ δὲ ταῦτα ἡ ναυμαχίη ὑπολαβοῦσα ἐς γόνυ τὴν πόλιν ἔβαλε.

Lionel Scott ad loc.:

As with us, the Greeks had the expression of being brought to one's knees; of men, e.g. in boxing (Simon Epig XXV Page) or warfare (5.92b; Aesch Ag 64), and of a country, as here and of the Persians in 480, Aesch Pers 929–30, ἐπὶ γόνυ κέκλιται.

A.F. Garvie on Aeschylus, Persians 929-930:

[F]or being brought to one's knees as a sign of submission cf. Sol. fr. 4a, Hdt. 6.27.3 ἡ ναυμαχίη ὑπολαβοῦσα ἐς γόνυ τὴν πόλιν ἔβαλε, E. IT 332–3, App. Bell. Civ. 3.30, Phryn. Soph. 71.11–13 de Borries. It is probably a metaphor from wrestling (cf. Ag. 63–4).

David Sider on Simonides, Epigrams 31.2:

[A] Greek wrestler lost a round/πτῶμα if any part of his body (other than the bottoms of his feet) touched the ground. (Three falls won the match.) Cf. the epigram on Damostratus, οὗ κατ᾿ εὔγυρον πάλην | ψάμμον πεσόντος νῶτον οὐκ ἐσφράγισεν (App. Pl. 25 = Philip 65 GP). Since it was often the knee that touched the ground first, a statement to this effect came to have a more general sense of "defeat"; cf. A. Pe. 913-14 [sic, read 929-30] Ἀσία δὲ χθών...| αἰνῶς αἰνῶς ἐπὶ γόνυ κέκλιται (but here Persian proskynesis is also evoked), Hdt. 6.27 ἡ ναυμαχίη ὑπολαβοῦσα [a technical wrestling term] ἐς γόνυ τὴν πόλιν ἔβαλε; see further E. N. Gardiner, "Wrestling," JHS 25 (1905) 20-1; W. Rudolph, Olympische Kampfsport in der Antike (Berlin 1965) 33; Ebert 184-5. (Gardiner changed his mind later, thinking that a wrestler could fall on his knee without losing the round: Athletics of the Ancient World [ Oxford 1930] 183, on which point he agrees with J. Jünther, Philostratos über Gymnastik [Leipzig 1909] 212.)