While the Greeks and Romans had personifications of fate in their mythologies, Christianity does not. However, the mindset still does not allow for free will. Redubbed predestination, the idea is that God knows everything, past, present, and future. For that to be the case, then everything has already been written. Nothing can be changed. There is no choice.
A consequence of this idea is that people can only be born to things. Every circumstance of life is dependent upon the circumstances of birth. Those born as peasants are peasants. They will never become anything different. Those with royal blood are inherently better than others. They have the blood to rule. The triumph of the merchant classes is slow in happening. Even by the time the Italian Renaissance comes, the idea of hereditary station is still strong with the European mind.
All of this rambling is to say that the idea of education as a means to power doesn’t exist. Merlin cannot get his power by mastering an ancient art. He does not train to it, he is not apprenticed to another magician. He is born with certain powers, which he uses to aid Arthur. Education, in general, is something very difficult to come by. Various guilds safeguard information more closely than the latest Apple products. The secrets of glassblowing, architecture, and many more disciplines were kept from all in order to safeguard the knowledge and skills from outsiders and competitors. For an interesting taste of this, look at the builders in Ken Follet’s The Pillars of the Earth (the book or the mini-series).
People with knowledge are only a step removed from accusations of witchcraft, too. The ability to create certain mechanisms, craft things in a new way, or use of medical knowledge could get someone into trouble very quickly. The entire medieval world was intolerant of such things, (not just the clergy, as some would say).