During medieval times, the only thing close to what we would call education was carried out by the church. Usually by monks and nuns, studying religious texts and similar items. Some of these schools tended to be much better at this than others, and essentially this gave the opportunity to those more gifted in academia to study further and it became more than just learning to read and write, it became more about study of the texts and what they could mean. The exceptional schools then slowly transformed into what were known as universities.
If you want more info here’s the link
https://history.stackexchange.com/questions/28819/why-were-the-first-universities-created/28848
