Complex sentence: Gallerani was a distinguished soldier until he killed a blasphemer in a fit of rage and was exiled from his home where he decided to live a life of total penance for his sin.
Split into simpler sentences: Gallerani was a distinguished soldier until, in a fit of rage he murdered a man he considered a blasphemer. As a result, he was exiled and decided to live a life of total penance for his sin.