The article concerns the barbaric word ἄγγαρος in Agamemnon 282 and its role in Aeschylean poetic and dramatic technique. Line 282 opens Klytaemnestra’s “beacon speech”, which is reckoned to be full of symbolic meaning and ambiguity, sending the spectator back to the fires of the sacked Troy. The commentators (Fraenkel, Judet de la Combe, Collard, Tracy) have noted that the word ἄγγαρος refers to the Achemenid institution of horsed courriers and trace back the Persian barbarian and therefore hybristic connotations of the tragic line. Tracy also mentions Herodotus’ report (IX 3) on the beacon post arranged by Mardonius after his sack of Athens in 479 BC. It is claimed that Aeschylus (and his spectator) kept in mind this event while writing (and performing) his tragedy. Still the purpose of such allusion, as well as the correlation between the beacon post and horse messengers in their historical and literary reality, remains unclear. An analysis of the Aeschylean imagery of the “beacon speech” sheds some light on the problem. The Aeschylean comparison of the light of the torch procession going from Troy to Argos with 155 a Persian horse messenger is based on three motifs found in the 5th and 4th century sources concerning Achaemenid pony express. In Herodotus and Xenophon it is characterized by its (1) miraculous, almost supernatural, divine speed and swiftness provided by (2) passing the message from one horse-rider to another and symbolizes (3) the power and splendour of the Achaemenid monarch and his empire. All three motifs are realized in Klytaemnestra’s speech either on a lexical or thematic level. Besides the poetics of this particular speech the barbarism ἄγγαρος is used for forming Klytaemnesta’s ethos, her masculine mind (androboulia), of which the clever invention of beacon post is a powerful and impressive symbol. The choice of a Persian word designating a Persian institution cannot be accidental in the context of lines 527–531 alluding to Persians 809–812 and general similarity between two Aeschylean plays observed by the critics. The sack of Troy is thereby assimilated with the sack of Athens, and Agamemnon himself – with a hybristic barbaric conqueror. These connotations are to be fully conveyed later in the text in the so-called “Carpet Scene”. Lastly, the problem of historical evidences of beacon post in Persia and Greece in the 5th century BC and its possible relation to the tragic text are investigated. As a conclusion, a suggestion is made that the word ἄγγαρος implies connotations of the forthcoming disaster and downfall awaiting arrangers both of the beacon post (Klytaemnestra, Agamemnon, Mardonius) and courrier post (Xerxes, Persians), even though they seem triumphant and victorious for the moment being. The semantics of the word ἄγγαρος draws up the ambiguity of the torch procession – a joyful piece of good news of victory, which soon turns out to be a disastrous defeat.