In the Greek Dark Ages that followed the collapse of the Mycenaean civilization, significant numbers of Greeks had emigrated to Asia Minor and settled there. These settlers were from three tribal groups: the Aeolians, Dorians and Ionians. The Ionians had settled about the coasts of Lydia and Caria, founding the twelve cities which made up Ionia. These cities were Miletus, Myus and Priene in Caria; Ephesus, Colophon, Lebedos, Teos, Clazomenae, Phocaea and Erythrae in Lydia; and the islands of Samos and Chios. The cities of Ionia had remained independent until they were conquered by the famous Lydian king Croesus, in around 560 BC. The Ionian cities then remained under Lydian rule until Lydia was in turn conquered by the nascent Achaemenid Empire of Cyrus the Great. The Persians found the Ionians difficult to rule. Elsewhere in the empire, Cyrus was able to identify elite native groups to help him rule his new subjects—such as the priesthood of Judea. No such group existed in Greek cities at this time; while there was usually an aristocracy, this was inevitably divided into feuding factions. The Persians thus settled for the sponsoring a tyrant in each Ionian city, even though this drew them into the Ionians' internal conflicts. Furthermore, a tyrant might develop an independent streak, and have to be replaced. The tyrants themselves faced a difficult task; they had to deflect the worst of their fellow citizens' hatred, while staying in the favour of the Persians.