Jolnir is the name used for Odin during Jul, which was the Viking Age Midwinter celebration. Here, in the shape of a traditional Swedish tomte, he comes with his characteristic one eye, fiber white beard, a body and hat made of soft felt.
The tomte figure represents the many different spirits that were very important to Viking Age Scandinavians. In folklore the tomte guarded the home and protected its people from misfortunes.
Midwinter celebrations in Viking Age Scandinavia were (and still are) known as Jul. A common practice, already appearing in Hrafnsmál in the year 900, is "drinking Jul". That points at the importance of gathering around the ceremonial toasts during the festivities. Odin, also known as Jölnir (Yule-er) and Jölföðr (Yule Father) was an important figure during this period. Midwinter is often connected to Odin and his wild hunt across the sky.