Complex sentence: The Battle of Sellasia was a war that took place in 222 BC between the armies of Antigonus III Doson, King of Macedonia and Cleomenes III, King of Sparta, the Spartan Forces were massacred and Cleomenes fled to Egypt.
Split into simpler sentences: The Battle of Sellasia was a took place in 222 BC between the armies of Antigonus III Doson, King of Macedonia, and Cleomenes III, King of Sparta. The Spartan Forces were massacred and Cleomenes fled to Egypt.