Complex sentence: The White Witch was born on an unknown date decades before the creation of Narnia and died in battle in Narnian year 1000, meaning that she lived for well over 1,000 years.
Split into simpler sentences: The White Witch was born on an unknown date long before the creation of Narnia. She died in battle in Narnian year 1000, meaning that she lived for well over 1,000 years.