Aeschylus in the Persians has the idea of the 'white horses' as the Chorus, the faithful council of the Persians, sings:-
έμαθον δ᾽ εὐρυπόροι-
ο θαλάσσας πολιαι-
νομένας πνεύματι λάβρῳ
ἐσορᾶν πόντιον ἄλσος,
πίσυνοι λεπτοδόμοις πεί-
σμασι λα-
οπόροις τε μαχαναῖς.
'And they have learnt to look upon the precinct of the deep when the broad-wayed sea whitens to foam beneath the tempest's blast, trusting in their finely wrought cables and their devices which give passage to their army.'
Or, as Gilbert Murray translates it:-
'We have turned us to the sea, and no fear is in our mind;
With our bridges cable-woven we have climbed from steep to steep;
We have seen the waves whiten in the fury of the wind,
We have faced the holy places of the deep.'