Complex sentence: She is best known for a heroic act of self-mutilation to avoid rape by Viking invaders: according to a ninth-century chronicle, she took a razor and cut off her nose in front of the nuns, who followed her example.
Split into simpler sentences: She is best known for a heroic act of self-mutilation, cutting off her nose to avoid rape by Viking invaders. According to a ninth-century chronicle, she took a razor and cut her own nose off in front of the nuns, who followed her example.