Homer, Iliad 11.69

οἳ δ᾽, ὥς τ᾽ ἀμητῆρες ἐναντίοι ἀλλήλοισιν
ὄγμον ἐλαύνωσιν ἀνδρὸς μάκαρος κατ᾽ ἄρουραν
πυρῶν ἢ κριθῶν: τὰ δὲ δράγματα ταρφέα πίπτει:
ὣς Τρῶες καὶ Ἀχαιοὶ ἐπ᾽ ἀλλήλοισι θορόντες
δῄουν, οὐδ᾽ ἕτεροι μνώοντ᾽ ὀλοοῖο φόβοιο.

Just as the reapers in the rich man’s field of wheat or barley 
drive the furrow opposite one another; 
the thick handfuls fall [to the ground];
so do the Trojans and Achaians, leaping,
cut each other down, neither side mindful of fearful flight.

Background
Homer’s Iliad is a seminal work in Greek literature. It tells of the Greeks fighting the Trojans and the wrath of the great Greek hero, Achilles.

Commentary
This is perhaps the earliest reference to barley in Greek literature. In this passage, barley is given equal weight alongside wheat. This is significant because such is not always the case in later texts. Several centuries later, in fact, there is a decided preference  for the consumption of wheat over barley.

Ancient Greek also preserves several words that refer to many different types/preparations/forms of barley. The use of κριθη is similar to the earliest references to barley beer, such as οινος εκ κριθεων (wine from barley).

Author’s Note
Homer (8th c. BCE?)
The great bard. He wrote the Iliad and the Odyssey – monumental texts in the western canon and the earliest preserved Greek literature.