Knight
A knight is a member of the Order of Chivalry who has sworn fealty to the Crown.
Did you know that "Only a Knight can create a Knight"?
Ever wonder why?
Because that's the way the system was set up lo those many, many years ago. http://www.sca.org/docs/govdocs.pdf
Governing Documents of the SCA, Inc. (PDF) - April 2001, revised November 2005 contains Corpora, the By-Laws, Corporate Policies, and the Articles of Incorporation Page 14, Section G The Crown 2. The Crown may elevate subjects to the Peerage by granting membership in one of the Orders conferring a Patent of Arms, after consultation with the members of the Order within the Kingdom, and in accordance with the laws and customs of the kingdom. Restriction: to advance a candidate to the Order of Knighthood, a Knight of the Society must bestow the accolade.
(A "keeper" posting from the Steps, Feb 2006.)
Additionally, even though a person may be the King or Queen, they cannot make someone a knight unless they have been knighted themselves. Aside from having a knight's hand on his shoulder [some say on sword] whilst making said person a knight, the King or Queen does not have the ability nor right to make someone a knight.
Likewise, the mere fact that someone has won Crown Tourney does not guarantee that they will be elevated to knighthood.
Where does this sort of thing get started? (sigh)
No, it's the other way around. It takes a knight to make a knight. If the king is not a knight then he has to have the hand of a knight on the sword. That's been that way from the start.
No, you don't have to be a knight to be king. You can (and it has happened) be an unbelted fighter and win Crown. Not to far back there was and unbelted Duke in Caid. Which means he was king twice and unbelted.
Yes, one can refuse a belt or become a Master at Arms. No one can force another to be a knight. No one can force you to become any kind of Peerage or accept an award if you don't want it for some reason. If I recall correctly, belts have been refused either here or in the West before.
I think the best thing to do with questions like this is go to the History of the West Kingdom web site and start looking around. You'll find the roots of "what and why we do things this way" there.
Viscount Jerald of Galloway, KSCA