However, it was mainly through oral tradition that Norse mythology flourished during much of this early period. Although many stories may have existed long before, the majority of the surviving tales and accounts from Norse mythology come from written sources primarily composed during the medieval period.
It wasn't until the Viking Age (from the late 8th to early 11th century CE) and in subsequent years that most of the Norse myths as we know them today got documented. During this time, skalds wrote their poetic verses, sagas were being told and eventually recorded, and various Eddas—notably the Poetic Edda and the Prose Edda—brought together these myths into manuscripts. Even later, some information about Nordic religion, legends, customs, and cosmology, such as in books by Snorri Sturluson, helped preserve significant insights into Norse mythology after the conversion to Christianity.