Complex sentence: Menzoberranzan was a city ruled by backstabbing and ambition, and House Baenre thrived in it, holding the greatest favor of Lolth longer than any other family in Menzoberranzan history.
Split into simpler sentences: Menzoberranzan was a city ruled by backstabbing and ambition, and Baenre thrived in it. It, the house, held the greatest favor of Lolth more successfully than any other family in Menzoberranzan history.