Conversation so far:
What University did Gottlob Frege attend?
University of Jena.
What did he study at Jena?
he attended approximately twenty courses of lectures, most of them on mathematics and physics.
Did he then transfer to Gottingen?
Frege continued his studies in Gottingen.
What did he study at Gottingen?
Gottingen, the leading university in mathematics in German-speaking territories.
Did he graduate with a degree?
Frege attained his doctorate.

Question: What did he do after he graduated?
Self-contained rewrite: What did Gottlob Frege do after he graduated?