Complex sentence: Gertrude Atherton made some controversial comments during her career, however amongst the most vicious and unprovoked was her shallow and cruel assault on Pio Pico, the last Mexican governor of California.
Split into simpler sentences: Gertrude Atherton made some controversial comments during her career. However, amongst the most vicious and unprovoked was her shallow and cruel assault on Pio Pico, the last Mexican governor of California.