Simplify the following text for a Grade 9 native English-speaking person.
Original: The decline of Chola power in Sri Lanka was followed by the restoration of the Polonnaruwa monarchy in the late 11th century AD . In 1215 , following Pandya invasions , the Tamil-dominant Arya Chakaravarthi dynasty established an independent Jaffna kingdom on the Jaffna peninsula and parts of northern Sri Lanka .
Simplified: After decline of the Chola power in Sri Lanka , different rulers ruled Sri Lanka , the Arya Chakaravarthi dynasty from 1215 .