From LitWiki

Hera is daughter of Cronus and Rhea, sister of Zeus and also his wife. Hera is goddess of marriage and childbirth. She is known for her jealousy of Zeus and her intrigues against him and his many human mistresses and illegitimate children. In the Iliad, Hera is a partisan of the Achaeans for two reasons. One is that main cities of Achaeans are under her protection. Another reason is her anger at the Trojans because of Paris’ decision to give the golden apple marked “for the fairest” to Aphrodite.