Complex sentence: The Wu emperor Sun Quan hated the Liaodong warlord Gongsun Yuan for breaking his promise to ally with Wu against Wu's rival state Cao Wei, and planned to personally lead an army to attack Gongsun Yuan.
Split into simpler sentences: The Wu emperor Sun Quan hated the warlord Gongsun Yuan for breaking his promise to ally with him against Wu's rival state, Cao Wei. He planned to personally lead an army to attack Gongsun Yuan.