I wonder if there is any regular event, which covers the entire kingdom (approximately every century or something) that affects the material plane. Or almost everyone knows what is happening, or simply that the powerful users of magic would feel it.
I love the great march of modron, but it is too long between events. Maybe a comet or celestial alignment? Something in that sense, however, would be good.
Answers that focus on story 5e are preferred, but they are also open to existing history.
Thank you, in advance, for your time and knowledge.