Invictus 13 Month Calendar

The first day of the year is Monday, 1st of Minerva, which always falls on March 22nd of the Gregorian calendar. The new year of the 13 month Invictus calendar begins with spring.
There are 13 months in the year, each comprised of 28 days, plus one *Solday* which is the last day of the year and technically the 29th day of Invictus, the 13th month. Every four years there is a Leap Day added on to the end of Septimus.
The months are:
1. Minerva 2. Aprilis 3. Maia
4. Juno 5. Julius 6. Augustus
7. Septimus 8. Octo 9. Nova
10. Deca 11. Janua 12. Februa
13. Invictus
The end of the year, Friday (the 26th), Saturday (the 27th) and Sunday (the 28th) of Invictus, are followed by “Solday”. It does not fall on a typical day of the week, ie Monday-Sunday, but on its own day. This special day brings the Invictus Sun Calendar to a total of 365 days in the year, ensuring the seasons and calendar coincide.
The Spring Equinox falls on the last Friday, Saturday, or Sunday of Invictus and Monday, Minerva 1st is the celebration of the New Year, which make for a long holiday celebration.
During the transition to the 13 month Invictus Calendar, one might choose to observe Gregorian days of the week instead (so Monday may be the 3rd for example instead of the 1st) or in conjunction with the Invictus calendar, observing the Roman names for the days of the Invictus week to avoid confusion. Then, in the future, transition to "Monday" through "Sunday" or stay with the Roman names.
Once enough have converted there are many conveniences in adopting the Invictus calendar; top among them is simplicity. Every month has 28 days. The month begins on Lunae/Monday and ends on Solis/Sunday. There is consistency, rhythm and balance.