The mages are not so uncommon in our world. Untaught mages would be a headache for everyone, that's why The First Emperor decreed the schools to be built for teaching children how to properly use their powers and how to be reliable citizens and pillars of the Empire.

You didn't have to be of some particular birth or anything. As long as you were a mage, you could go and learn. A simple exam was there to determine whether you had potential as a mage to be taught. The Empire would pay for you. The only thing you had to do was to be a good student and study diligently.

Aside from teaching magic, the schools had yet another meaning - to get children who would later hold power in the Empire acquainted with each other.

As no one could predict how their kids would turn out (the distribution of powers is completely random, and even now we don't know why some people have magic while others don’t), there were classes for kids of mages and officials who didn't have magical powers.

They also didn't have to pay and were taught how to deal with strategizing and paperwork. You don't have to be a mage to be smart, after all. Many managing roles don't require involvement of mages, and it is good to pass this work to capable people. Even if mages are not rare, they are not common either. There is too much work for them to make them deal with trivialities.

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Then again, trivialities should be managed by someone, and those people hold the power of law in their hand. It was a brilliant idea of The First Emperor to make them study together. This way they could understand the importance of cooperation between mages and officials.

The third type of classes was for those powerful and wealthy merchants.

For them, to get into the schools, they had to pay tuition fees. It was the mark of their ability. If the merchant family couldn't afford the exorbitant tuition fees, their children were deemed unworthy of entering the ranks of higher society. For those powerful merchant families, it was undoubtedly beneficial to have connections with mages and officials, so no one complained about the price.

The rumors were if a school had two or three merchant patrons the Empire didn't even need to worry about costs for all other students.

This system has been in place since then and is working the same way up to this day.