The Pandidakterion (university in Byz era) was the first to REMOVE religious education & astrology. For comparison the Academy of Athens in 4th c. AC mixed magic & philosophy. So the Byz higher education wasn’t “Orthodox”, it was more Platonic w/ philosophy, math, law & medicine.
It was founded by Emperor Theodosius II in 425 AC, and since then it was under the sponsorship of the Emperors. Education was free, no cost. Cyrus of Panopolis, epic poet, philosopher and a lover of Greek arts, played key role in its foundation.
From the beginning it never taught religious education. So, we see secular higher education being introduced in the middle of a … “theocracy”. Again we see the same in modern history. Christians (e.g. Quakers) introducing secular state in US, spreading in the rest of the west.