The Greek city-states were originally a series of independent kingdoms and democracies that dominated the land around their city. They fought one another and were only united when fighting a common opponent such as the Persian Empire in the Greco-Persian War of 490-330 BC. However, after the Peleponnesian War, they fell under Sparta's dominance, but were conquered by the Macedonian Empire in 338 BC after the battle of Chaeronea. They gained autonomy after Alexander the Great's death in 323 BC, and by 270 BC, they were all under the banner of Sparta.
The Greek Cities were targeted by several large empires, as they were scattered across the map: the main ones were Thermon and Sparta in Greece, Pergamum in Asia Minor, Syracuse in Sicily, and Rhodos in Rhodes (Athens was a rebel settlement later captured by The Greek Cities). The Syracusans were conquered by the House of Scipii in 270 BC, Sparta and Thermon by the House of Brutii in the course of the 270s and 260s BC, Pergamum was annexed by the Romans soon after the Battle of Chios in the 2nd century BC, and Rhodes was conquered by the House of Julii.