Final answer:
Apollo sends a plague on the Greeks in 'The Iliad' because Agamemnon dishonored Apollo's priest Chryses. This reflects the ancient Greek belief in divine influence on human affairs and the gods' response to honor or dishonor.
Step-by-step explanation:
The god who inflicts a plague on the Greeks at the beginning of The Iliad is Apollon, also known as Apollo. The plague is sent because Agamemnon, the Greek king, dishonored Chryses, a priest of Apollo, by taking his daughter Chryseis as a war prize and refusing to return her when Chryses offered a ransom. In response to the priest's prayers, Apollo shot down arrows of plague into the Greek camp, causing the death of many soldiers.
The narrative demonstrates the belief in divine influence on human affairs, which was a prevalent theme in ancient Greek literature and mythology. The Greeks interpreted many natural and social phenomena as indications of the gods' displeasure or favor, as illustrated through tales of divine retribution or assistance in times of conflict.