Complex sentence: Hundertwasser's father Ernst Stowasser died three months after Hundertwasser's first birthday.Also the Second World War was a hard time for Hundertwasser and his mother Elsa, as she was Jewish.
Split into simpler sentences: Hundertwasser's father Ernst Stowasser died three months after Hundertwasser's first birthday. The Second World War was a hard time for Hundertwasser and his mother Elsa, as she was Jewish.