What was the main purpose for having knights?

The main purpose of having knights was to serve as heavily armed and armored cavalry in medieval warfare, providing military support to their lords and protecting their lands. Knights were also responsible for maintaining order and enforcing the law within their territories. Beyond their military role, they played a crucial part in the feudal system, often receiving land or fiefs in exchange for their loyalty and service. Additionally, the knightly code of chivalry promoted ideals of honor, bravery, and loyalty, shaping social and cultural norms of the time.