Benvenuto Cellini, who in the 16th century killed repeatedly without remorse and without being punished. He stabbed his brother’s murderer to death with a long twisted dagger that he drove downward through the man’s shoulder. He also killed a rival goldsmith and shot an innkeeper dead – and recounts all these crimes in his autobiography. He escaped being executed because he was so admired as an artist. In those days, geniuses really could get away with murder.