What is a good thesis statement about medieval knights? I have written that knights emerged to help local nobles control their world.

You could write about the societal influence of knights and their clash with religious tradition during that time. Knighthood is an interesting outlet through which to explore medieval values, especially in reference to the Christian church's role among the population (as Christians dominated the religious environment of Western Europe during that time). During the medieval era, there were two types of "heroes": knights and saints—but one couldn’t necessarily be both. The notion of sainthood is in many ways oxymoronic in concurrence with knighthood. Saints were chaste; knights married and had children to carry on their legacy. Saints were expected to live in poverty, but the public understood poverty to be a direct threat to the preservation of a knight’s honor. While saints prayed and read scripture, knights went into battle alongside kings and helped eliminate the enemy by any means necessary. There was one thing saints and knights did have in common, however. They were both meant to serve as exemplary individuals, but in different capacities.

This all presented a challenge to the church, as Christianity was confronted with balancing tradition and scripture with an unstoppable progression of culture among the populace. Considering this context, one may wonder how a knight or a warrior could be a “good” Christian, or perhaps whether it was possible for them to be eligible for canonization as a saint (although to date, there are no canonized knights). Potential answers to this theoretical question depended largely on the medieval church’s attitude towards chivalry. In particular, it is important to consider the church’s reaction to warriors, tournaments, and the general notion of competitive glory.

Throughout this period, the church found ways to justify violence in the context of fighting to preserve Christian authority. For instance, the Crusades and the Knights Templar were outlets for people to exhibit their aggression and satiate their competitive appetite, while also remaining “good” in the eyes of the church.

Aside from the Crusades and the Knights Templar, some good specific examples you could use in this exploration are William Marshal, St. Louis (or King Louis IX), St. Joan of Arc, and St. Francis of Assisi. While William Marshal was never canonized, the cases of Joan of Arc, Louis IX, and even Francis d’Assisi (before his spiritual awakening) demonstrate that engaging in violence did not prevent one from being a saint.