The Histories tell the story of the war between the Persian Empire and the Greek city-states in the 5th century BC. Herodotus traveled extensively around the ancient world, conducting interviews and collecting stories for his book. The rise of the Persian Empire is chronicled, and the causes for the conflict with Greece. Herodotus treats the conflict as an ideological one, frequently contrasting the absolute power of the Persian king with the democratic government of the Greeks.