The Scandinavian people of the Viking Age, who were surrounded by and lived in raw nature, believed that everything in nature had a spirit. It was incredibly important for Vikings to communicate with nature spirits, the spirits of their ancestors, and to cultivate their own strong spirit.
No diety personified nature to the Vikings more than the Norse goddess Fjorgyn. The Old Norse name Fjörgyn means Mother Earth, planet Earth, or land that is earth. Fjorgyn is the Norse people's oldest living Æsir goddess, their main fertility goddess, and the personification of the fertile earth. According to the Prose Edda, everything that happens on the planet Earth is because of the goddess Fjorgyn.
According to Snorri's Prose Edda, Odin created the Earth and fell in love with her. Fjorgyn became Odin's first wife, or mistress, and bore him a son, Thor, the God of thunder. This union between the sky god and the Earth created the strongest of all the Norse gods, a product of the earth's power.
Fjorgyn nurtures the divine children and protects mortal children, and thus humanity. Everything we humans surround ourselves with is created by Mother Earth, and everything that lives and then dies becomes the Earth. Fjorgyn nurtures all living things and takes everything that dies. The Norse people knew that our planet was alive and had a life. They showed Fjorgyn respect and knew that they had to take care of her fertility, because without her, there is no life.
Vikings knew that the Earth was incredibly old and had powerful forces. They also knew that when they cultivated the earth she became more fertile, and because of this they had a much better life. Vikings used earth in sacred rituals involving life events. In Sigrdrífumál, the Valkyrie Sigrdrifa (Brynhild) teaches her magic spells to Sigurd, in appreciation for his rescuing of her. The verse she uses mentions Fjorgyn, and is one of the oldest recorded greeting we know from the Norse culture:
Hail Asas,
Hail Asynjes,
Hail bounteous earth!
Words and wisdom
give to us noble twain,
and healing hands in life!
Hail to the gods !
Ye goddesses, hail,
And all the generous earth!
Give to us wisdom
and goodly speech,
And healing hands, life-long.