Hyperboreans
The race of people who were assumed to live in a land of perpetual sunshine and abundance beyond the abode of Boreas (North Wind).
The Hyperboreans were said to have interacted with the Greeks until two of their messengers, Hyperokhe (Hyperoche) and Laodike (Laodice), failed to return from the sacred island of Delos after delivering tributes for the shrine of Apollon.
There were also two graves at Delos for two virgins, Opis and Arge, who came from Hyperboria before Hyperokhe and Laodike, who were accompanied by the gods (probably Apollon and Artemis) and were honored by the Delians in hymns and ceremonies which required young men and women, before their marriage, to cut their hair and place it on the graves of the two girls.
Histories, book 4, chapters 13, 32-36