Complex sentence: Tepe worked for Vincenz Statz (well known Gothic Revival architect of Germany) in Cologne in the restoration and completion of the Cologne Cathedral from 1865 to 1867, which gave him on-the-job training.
Split into simpler sentences: Tepe worked for Vincenz Statz (well known Gothic Revival architect of Germany) from 1865 to 1867 in Cologne. He was involved with Statz in the restoration and completion of the Cologne Cathedral, which gave him on-the-job training.