Complex sentence: His mother was raised as a Catholic in the Sudetenland, the daughter of the manager of a graphite mine who had been the first socialist in his village around 1890 or 1900.
Split into simpler sentences: His mother was raised as a Catholic in the Sudetenland. She was the daughter of the manager of a graphite mine who had been the first socialist in his village around 1890 or 1900.