Complex sentence: Chen Wan later fled to Qi, a major state to the east of Chen, and established the Chen (Tian) clan there, which grew increasingly powerful over the centuries and eventually usurped the Qi throne.
Split into simpler sentences: Chen Wan later fled to Qi, a major state to the east of Chen, and established the Chen (Tian) clan there. The Chen clan of Qi grew increasingly powerful over the centuries, and eventually usurped the Qi throne.