Common in literature, but not in real life, a knight who was not in service to a lord was called a knight-errant.
a black knight was a knight who either didnt serve a king or didnt want his king to be identified
to serve the king and country always
well, usually in the middle ages,cooks for knights or vassals were squires. a vassal is a knight that owned land from his lord. a squire is a knight in training.the job of a squire( age 12-16) is to serve his knight until he become one. they made meals for the knight, learned how to serve it, and also learned all the things that knights do.
Serve their knight and make sure he had everything he wanted.
In midevil times, to become a knight you neede to be the son of a knight. At age 7 you become a page, which is like "knight school", at age 14 you become a squire, which is when you serve a kight, and at ages 18-21 if you have mastered page and squire, you become a knight.
They went to Crusades to help serve their country and religious beliefs.