Complex sentence: At the end of the war he went back in Germany in Thuringia (that at the time was East Germany) and soon in 1950, after leaving all his possessions, he repaired to Berlin.
Split into simpler sentences: At the end of the war he went back Thuringia in Germany, which at that time was part of the former East Germany. In 1950, after leaving all his possessions, he repaired to Berlin.