Complex sentence: Antony defeated the forces of Gaius Pansa and Octavian, which resulted in Pansa suffering mortal wounds; however, Antony was then defeated by a surprise attack from Hirtius.
Split into simpler sentences: Antony defeated the forces of Gaius Pansa and Octavian, which resulted in Pansa suffering mortal wounds. However, Antony was then defeated by a surprise attack from Hirtius.