Hi kael123, and welcome to the .Org!

If I remember correctly, the University does not offer any benefits, but it is a prerequisite for the College of Surgeons and Military Academy for Catholic and Orthodox factions (the Grand Mosque is the prereq for Muslims). It does not unlock any troops.

The College of Surgeons offers a 40% bonus to happiness in the province it is built in, and supposedly also increases the lifespan of your generals and family members.

The Military Academy will make units trained in the province Disciplined. The actual mechanics of this upgrade is unclear, but generally this will make your troops easier to control and harder to rout. If you are playing as the Turks, the Military Academy is necessary for the 3 types of Janissary units, some of the best in the game.