The most powerful Chola ruler was Rajaraja I. He became king in 985 AD and expanded his control. He also reorganized the administration.
Under him, the kingdom of the Cholas gained ground and emerged as an empire. He conquered the kingdoms of southern kingdoms and also conquered Sri Lanka and Kalinga in the North-east..
Rajaraja’s son, Rajendra I raided the Ganga valley, Sri Lanka and countries of South East Asia, raising a navy for these campaigns.
Temples of Thanjavur and Gangaikonda-cholapuram, built by Rajaraja and Rajendra, are sculptural and architectural marvels.