When Adonis was an infant, Aphrodite put him in a chest and gave him to the Greek goddess of the Underworld, Persephone, to be taken care of.
Persephone, however, was so much charmed by the extraordinary beauty of Adonis that, when he had reached manhood, she refused to give him back to Aphrodite.
In order to judge fairly, Zeus (or, according to another myth, the Muse Calliope) allowed Persephone to keep Adonis in the Underworld for four months every year. Four months Adonis should also spend with Aphrodite and the remaining four months he could stay with whomever his heart longed for. Adonis opted for Aphrodite.