This world has two moons, one blue-green and the other, white.
A double lunar eclipse of both blue and white moon occurs every 105 years. This particular eclipse renders certain parts of the World completely dark. In some parts the darkness can last for a full month.
Because this phenomena of darkness is isolated in particular to certain regions, most humans do not concern themselves with the cycles of darkness.
However, there are significant shifts in tides and migrations of animals during this period.
The last 105 year eclipse occurred in the Golden Calendar Year 1200.
I’m concerned about a little multiplying issue here. If the blue-green moon eclipses every 11 years, how could a double eclipse ever happen in a 105 year period if this is not a multiple of 11?
Maybe you meant double eclipse every 110 years?
Urk. Went back to my notes (in another journal) and it was supposed to be 21 years, not 11. I’ll have to check to see how this error has propagated in the text (as I may not have referred back to the original journal). Thanks for pointing that out. The eclipse of one is not particularly important to the story, so for now will remove it.