Resources for Those Wanting to Learn about Pre-Christian Time Reckoning in Northern Europe and its Application in Modern Heathen Traditions
Throughout the history of the modern Neo-Pagan movement, the calendar that has been used by most practitioners has been either the Wiccan Wheel of the Year or another calendar heavily influenced by it. The Wheel of the Year draws largely upon a mixture of Celtic (Gaelic) and Anglo-Saxon traditions, splitting the years into quarters with quarterly and cross-quarterly celebrations and beginning the year at the end of October with the originally Gaelic festival of Samhain.
The calendars that have come to be popular for the majority of the modern Heathenry movement have undoubtedly been based in this calendar, with the major changes being to the names of certain celebrations. On the calendar created by Stephen McNallen for the AFA, Lammas became Freyfaxi, Mabon became Winter Finding, Samhain became Winter Nights, etc. Other organizations such as Forn Sidr of America, The Ásatrú Community, etc. have created their own versions of the calendar as well, but at their roots they all exist essentially as a modification of the Wheel of the Year concept.
More (relatively) recent research and scholarship has brought a greater awareness of older time reckoning systems within Heathen circles as well as amongst history enthusiasts. Some of this has focused on the Old Icelandic calendar as well as the primstav tradition, and while both of these have validity to them the Old Icelandic calendar already had some changes to how it worked from the older system and the primstav used a standardized dating system based in the Julian calendar. Still, these are both useful tools in attempting to reconstruct the pre-Christian (or at least pre-Julian) calendar systems of the Germanic, and particularly Scandinavian, peoples of Northern Europe.
Why is this at all important in an age with the Gregorian calendar used most everywhere and especially for those outside of Scandinavia? Because for those trying the build an understanding of or relationship with these cultures, or even just more connected to the earth in general, the way they reckoned time helps to understand their relationship and connection to their environment, the flow of seasons, how they viewed the different parts of the year and adjusted their activities accordingly, etc. It helps to understand the "why" behind the ritual cycle, even in the names of the months themselves.
Below are a few of the primary resources that I have found helpful in learning about these topics, as well as a graphic representation that I have made based on my research so far to represent the reconstructed Old Norse lunisolar calendar. Note that I don't claim to be an expert on this topic, so I could certainly be wrong in some of the details, and some of the months also have multiple names from which I chose one to use. Also, there were multiple time reckoning systems in use during the period, including a week-counting system, so there can also be conflicting information depending on which is being considered.
"Jul, disting och förkyrklig tidräkning: Kalendrar och kalendriska riter i det förkristna Norden" by Andreas Nordberg
- Available as a free PDF, the majority of this is written in Swedish, but it contains a fairly concise English summary at the end. It focuses primarily on Old Norse Jól (Yule) as well as the Dísaþing/Disting and Dísablót in Sweden, but it touches on other celebrations and uses these to establish the overall scheme of the lunisolar calendar system.
"The Festival Year: A Survey of the Annual Festival Cycle and Its Relation to the Heathen Lunisolar Calendar" by Josh Rood
-Also available as a free PDF, this paper expands upon Norberg's work as well as others' and goes through the overall festival year of the pre-Christian Scandinavians.
"The Lunisolar Calendar of the Germanic Peoples: Reconstruction of a bound moon calendar from ancient, medieval and early modern sources" by Andreas Zautner
-This book is sort of a dive into a number of different ancient to early modern calendar systems, but it uses all of these to reconstruct lunisolar time reckoning systems not only for Scandinavians, but for other Germanic peoples as well. It's a great read for those interested in pre-Julian time reckoning in Northern Europe as well as Medieval calendar systems in general.
"The Nordic Animist Year" by Rune Hjarnø Rasmussen
-Similarly to Zautner's book, Rasmussen draws upon a variety of Medieval calendar systems in his work, but his goal, rather than reconstructing an Old Norse calendar is to create a modern calendar based in animist traditions of Northern Europe. It undoubtedly uses the lunisolar system as a base and takes a lot from Old Norse sources, but it also incorporates later traditions which are based in animist knowledge and have value in establishing a system of seasonal animism.
And lastly, my Old Norse lunisolar calendar representation. Each month starts on a new moon, represented by a black dot, and the festivals are shown at the full moons, being white dots: