The origin of German formal "Sie"
Duolingo grammar notes for 'Formal You' included the following:
'When spoken, "they" and formal "you" are identical. So, in a way, Germans formally address people like "How are they today?"' So I got curious and was wondering that maybe the origin of the formal "Sie" is actually in the way that the kings addressed themselves with "we" while speaking?
German actually has another formal you for kings/majesties, the 'Ihrzen'. You would say 'Ihr' to the king, if we had one.
"Was denkt Ihr dazu, eure Hoheit?" (What do you think about it, your majesty?)
I always thought that it comes from French, where they use the formal form (vous instead of tu) even more often. French had a huge influence on the German language in the past, because it was the language of the aristocracy. But I never thought about why it is like this in French. o_o
I tried to google it, but I only find articles on why German should stop using Sie for the formal form. Well..
But it sounds plausible that the idea was to use another plural form (3rd person plural instead of 2nd) to 'give' the other person a comparable status to a majesty.
To add to this, Ihr was the formal you for everyone for a long time. Based on the literature I've read, I think the switch happened some time in the 1800s. This is consistent with the French using plural for formality, but also English - "thou" is "du" and "ye" is "ihr." You comes from ye. I assume the royal we is also connected to this. Unfortunately I don't know why Ihr changed to Sie, either, though.
There also was a time when people were formally addressed with "Er / Sie" (third person singular): "Erzähle Er mir von Paris (imperative)! Hat Er den König gesehen?"
I think the idea was that the further away from "you" you go, the more respectful it is, and you can do that by a) pluralising, b) going to third person. And then, of course, you capitalise the pronoun to add importance. That way, you get "Ihr" by plural, "Er/Sie" by third person, and finally "Sie" by plural plus third person.