"The Sea Mother's Gift" is a short story by Laura Frankos, published in The First Heroes, (Tor, 2004). It is set around 1160 BC, when the eruption of the Hekla volcano in Iceland caused catastrophic climate change in northwestern Europe. The story focuses on an agricultural community in the Orkney Islands, who interpret the sudden change as a battle between gods. They pray to their patron goddess, the Mother of the Sea, for guidance on how to survive the attacks by the evil god Lord Father Winter and his fearsome accomplice, the sea monster Klevey. Sheep farmer Dett receives a prophetic dream which contains clues to a new agricultural strategy to combat the crop shortage.
With its focus on gods and prophecies, the story can be considered fantasy, however Frankos is deliberately vague on whether any supernatural activity is actually happening, as Dett's dreams, and a waking vision he has early in the story, can be explained away as insights from his own subconscious. The story is set in a historical period, yet the culture and demographics come primarily from Frankos' imagination - as our knowledge of British history prior to 52 BC or so is limited to interpretations of archaeological remains, Frankos has a virtual carte blanche in these matters, and nothing about the depicted society can be falsified.