In return for their service as good stewards of the land and readily available warriors, the King owes Knights, Barons, and other high nobles protection, honor, and a return of money, food, etc., in times of hardship. In the SCA this structure underlies our Society, although not nearly as rigidly as in the medieval days. Our King, the head of our Kingdom and our liege lord, has fought in a Crown Tournament for the right to make his Lady Queen and the right to wear the crown. Royalty are bound by the laws and customs of the kingdom and the Society as a whole, but still wield significant power over their subjects. Of course, four to six months later there is a new King, with different ideas.
Life can get interesting.
Fighting in the SCA evolved from what happened when two armed knights were unhorsed and had to fight on the ground. It resembles nothing so much as medieval foot tournaments. SCA fighting does have rules. The first, and most important rule, is that each and every fighter on the field has honor. Rattan is that bamboo-y stuff, only with a solid core, that furniture is made of.