Complex sentence: He sent ambassadors and envoys to Leukon as if he were wanting an alliance, but in reality, he sent them there to look at Leukon's army, upon learning the details, Memnon waged war on Leukon and landed on Bosporan soil.
Split into simpler sentences: He sent ambassadors and envoys to Leukon as if he were wanting an alliance, but in reality, he sent them there to look at Leukon's army. Upon learning the details, Memnon waged war on Leukon and landed on Bosporan soil.