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"?
Every 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.