As humans began to grow in numbers, they began to create civilizations for themselves in order to better survive, and as those civilizations grew, there came to be a divergence of roles for people to perform. The most universal of all these was the Warrior Elite, a class of people who were part of the lesser nobility and would function as officers and generals in times of conflict. For Japan it was the Samurai, for Iran it was the Persian Immortals, and for Europe in the 9th to late 15th century, there were the Knights. Let us look at what knights were, how they grew and changed through history, their eventual decline, and even a few chivalric orders.
Sikes, David, "Knights of the Middle Ages" (2020). History Class Publications. 65.