In the 'Middle Ages' a squire served as the personal assistant of whom?

in the later period, what would potentially end a squire's apprenticeship with his knight? And, in the later period, what would allow the squire to advance to knighthood, if the transition was not assumed.

Guessed right thanks to "A Knights Tale". One of our favorite movies.

thanks to Game of Thrones I know this answer 😁

All answers are correct, as each would need a squire to prepare for battle or the joust. A king's squire would be a higher rank.