Good Morning, Afternoon, Evening, Night!

Mark it was sent to  Mr B from a friend I thought it looked interesting enough to share here on the forum.

I wonder why they picked 823 years? 823 happens to be a prime number and if you go back 823 years you get to 1198, now idea what was happening then or if they even used the same date system as now.
I wonder where my ancestors were in 1198 and how many of them would their be? It would have been a lot. And if just one of them had had an accident, I wouldn't be writing this now.
Anyway,good evening.