Q. Who was the earliest known Chola King who conquered Sri Lanka and ruled it ? Answer: Elara
Notes: The earliest known Chola king to conquer Sri Lanka was Elara. He ruled over the island for 50 years. The Mahavamsa mentions that a Chola prince named Ellalan conquered the Rajarata kingdom of Sri Lanka in 235 BCE. He invaded with the help of a Mysore army.