The word Yule (or Jul), Old Norse Jól or Jöl, was used to describe a feast and is still used today in the Scandinavian languages as the normal term for Christmas.
We find the oldest written source of Viking Yule celebrations in the Old Norse poem Hrafnsmál ("Raven Speech"). This poem was composed around the 9th century CE by the Norwegian skald Þorbjörn Hornklofi. Hrafnsmál is mainly about a conversation between an unnamed Valkyrie and a raven, who discuss the life and martial deeds of King Harald Fairhair. One passage claims that he would spend Yule on his warship in battle if he had his way: