The basis for this whole thing is really boredom and some overly curiousness into certain things. THen again, that's the start of a lot of the setting additions on this site i guess, so I guess its not all that bad, is it?
Anyways, with the introduction of the Shogunate dating system from Exalted: the Outcaste, we now have a general idea of when the Terrestrial Shogunate officialy began. The current default year for the game, Realm Year 768, is the eleventh year of the 11th Epoch of the Terrestrial Shogunate. Now, each Epoch is 125 years long and ten have finished so far. This means that the Shogunate started 125x10 + 11. Or, in simplistics sake, 1261 years ago.
So what's this have to do with anything? Nothing much really. Though, it made me think. The current Realm calendar is based much on the dating systems of most nations. It starts with a specific date,a nd then just numbers from there. However, the Shogunate drew on Japanese dating systems, resetting the time unit after a certain time (In this case, a 125 year period, rather then Japanese ruler reigns). What this made me think is "Hey, maybe the Old Realm had its own dating system."
And so brings this bit of nonsense you see here:)
Before one can go about building a calendar for a culture that is now dead, and who's dates haven't been used in centuries, we have to think of how we are going to do this whole thing in a way that is different fromt he standard XY Number system as well as the Japanese Epoch system, but still showing some logical progression. As such, we gotta work out some minor things.
First off, we are goign to assume that the actual 425 day calendar remains pretty much intact. Luna doesn't seem to vere of schedule too much, and Calibration existed in the Old Realm and with the existance of beings like Five Days Darkness, indicate that it may even predate the gods themselves. So we'll keep these the same. Now, as to what they name the months and seasons, I would assume thos would remain about the same as well. The same sasons seem to predate the gods as well, as Five Days Darkness once again hints to the Court of Seasons being pretty damned old.
Now, these seasons might of been rather arbitary in the Old Realm. With the Solar Deliberative bossing the Bureau of Seasons around as much as it did, I think it was just a general calendar of what to expect. But it was probably more or less stable then the modern calendar, as the gods don't seem to be trying to make things as complex as back in the day.