Answer: Cyrus pursued a policy of conquest.
Step-by-step explanation:
Coming to power, he had to acknowledge the authority of the Media Empire. However, in time, he started a rebellion by conquering the Media Empire's capital, Ecbatana. After this success and the territorial expansion of the Persian Empire, he went to war with Lydia. The last empire on the list of Cyrus' conquests was the great New Babylonian Empire. After the fall, Cyrus proclaimed himself king of Babylon. Until that moment, the empire of Emperor Cyrus was the largest ever in history.