§ 333 — D. B. Monro Grammar of the Homeric Dialect 1

The chief use of the Adversative Particle δέ is to show that a Clause stands in some contrast to what has preceded. Ordinarily, however, it merely indicates the continuation of a narrative (i.e. shows that the new fact is not simultaneous). It is especially used to introduce a parenthesis or subordinate statement (whereas τε introduces something parallel or coordinate): e.g.—

νοῦσον ἀνὰ στρατὸν ὦρσε κακήν, ὀλέκοντο δὲ λαοί,

οὕνεκα κτλ.

Here a prose writer would say ὀλεθρίαν, or ὥστε ἀπόλλυσθαι τὸν λαόν, or ὑφ' ἧς ὁ λαὸς ἀπώλλυτο, &c. So—

Ἀντίλοχος δὲ Μύδωνα βάλ', ἡνίοχον Θεράποντα,

ἐστλὸν Ἀτυμνιάδην, ὁ δ' ὑπέστρεφε μώνυχας ἵππους,

χερμαδίῳ ἀγκῶνα τυχὼν μέσον.

I.e. ‘struck him as he was turning the horses.’

δέ is nearly always the second word in the Clause. It is occasionally put after (1) a Preposition and Case-form, as ἐπ' αὐτῶν δ' ὠμοθέτησαν, or (2) an Article and Numeral, as τῇ δεκάτῃ δ' κτλ.: but not after other combinations. Hence καὶ δέ, as Il.7.113 καὶ δ' Ἀχιλεύς and even Achilles (never καὶ Ἀχιλεὺς δέ, as in later Greek).