What point was that?
I almost never see a nice orthodox reflecting post-1000 start in that region because pagan will just flip between pagan until something silly happens.
So it would be bizarre to see a "nice" border starting from Charlemagne Date.
And it is 90% likely to not be the start he used for his screenshot (aqua).
Nearly all of my games are Charlemagne Date at least for me. So I have little experience to suggest otherwise.