Complex sentence: Hertervig studied painting at the Arts Academy of Düsseldorf from 1852, as the private pupil of Hans Gude, until he experienced a temporary mental breakdown two years later, and moved back to the Stavanger area.
Split into simpler sentences: Hertervig studied painting at the Arts Academy of Düsseldorf from 1852, as the private pupil of Hans Gude. In 1854, he experienced a temporary mental breakdown, and moved back to the Stavanger area.