Complex sentence: After high school (Altes Gymnasium Oldenburg AGO) he went to study medicine first at Zürich University in 1851, and then, two years later, at the University of Würzburg, where he had Rudolf Virchow as his teacher in pathology.
Split into simpler sentences: After high school (Altes Gymnasium Oldenburg AGO) he went to study medicine first at Zürich University in 1851. This was where he had Rudolf Virchow as his teacher in pathology.