Complex sentence: At the University of Copenhagen, he first studied theology, then science, but in 1886, he left the university and became employed as a teacher at Slomanns School in Frederiksberg, where he stayed until his death.
Split into simpler sentences: At the University of Copenhagen, he first studied theology, then science. After leaving the University he was employed as a teacher at Slomanns School in Frederiksberg, where he stayed until his death.