Complex sentence: The rogue Rider Galbatorix captured the capital city, Urû'baen (then called Ilirea), where he took King Angrenost's throne and titles for his own, thus becoming the ruler of the Kingdom.
Split into simpler sentences: The rogue Rider Galbatorix captured the capital city, Urû'baen (then called Ilirea). He took King Angrenost's throne and titles for his own, thus becoming the ruler of the Kingdom.