DittoCongrats on wrapping it. That was quicker than expected.
I had to solve that mystery also. My solution was to go to a city with a barracks (Saigon) and create an army and upgrade the catapult to Horse Artillery.While clearing the neighborhood, I get another Leader! It's actually hard to know where to send him.
You mentioned Universities were not going to help. I don't think Factories or Power Plants were going to help much either and Horse Artillery is nice to have vs Infantry.