The raven is a common iconic figure in Norse mythology. The highest god Odin had two ravens named Huginn and Muninn ("thought" and "memory" respectively) who flew around the world bringing back tidings to their master. Therefore, one of Odin's many names was the "ravengod" (Hrafnaguð).
This pair of earrings is based on a a Vendel period fibula brooch based on a find from Gotland in Sweden dating around 600 AD. The original version is now in the Statens Historiska Museum in Stockholm.