This is not your normal Gregorian calendar. This is the ancient Icelandic almanac for 2020 which has been integrated with the Gregorian calendar for easy understanding.
The calendar features the Old Norse seasons, months, weeks and days. It features important Norse pagan dates such as blots, festivals and other celebrations. In the 2020 version, improvements have been made to better explain the thought of time in the Viking era and explanations has been added which will guide you in finding your own Viking birth date!
The 2020 version features landscape photographs taken by Gaui H Pic from various locations in Iceland.
Note that this is available here in very limited numbers as these are expected to sell on Amazon.co.uk where the majority of the inventory resides.