Explanation:

The founder of the Chola Empire was Vijayalaya, who was first feudatory of the Pallavas of Kanchi. He captured Tanjore in 850 A.D. He established a temple of goddess Nishumbhasudini (Durga) there.
Aditya I succeeded Vijayalaya. Aditya helped his overlord the Pallava king Aparajita against the Pandyas but soon defeated him and annexed the whole of the Pallava kingdom.
By the end of the ninth century, the Cholas had defeated the Pallavas completely and weakened the Pandyas capturing the Tamil country (Tondamandala) and including it under their domination He then became a sovereign ruler. The Rashtrakuta king, Krishna II gave his daughter in marriage to Aditya.
The climax in Chola power was achieved under the successor of Parantaka II, Arumolivarman, who crowned himself as Rajaraja I in 985 A D the next thirty years of his rule formed the formative periodof Chola imperialism.
The Chola kingdom grew under him into an extensive and well-knit empire, efficiently organized and administered and possessing a powerful standing army and navy. Rajaraja began his conquests by attacking the confederation between the rulers of the Pandya and Kerala kingdoms and of Ceylon. Polonnaruva became the capital of Chola province in North Ceylon after the defeat of Mahinda V, the Ceylonese king.
He also annexed the Maldives. Elsewhere, several parts of modern Mysore were conquered and annexed which intensified their rivalry with the Chalukyas. Rajaraja built the magnificent Shiva temple of Brihadeshwara or Rajaraja temple at Thanjavur which was com¬pleted in 1010. It is considered a remarkable piece of architecture in South Indian style.
Rajaraja I also encouraged Sri Mara Vijayottungavarman, the Sailendra ruler of Sri Vijaya to build a Buddhist Vihara at Negapatam. This vihara was called ‘Chudamani Vihara’ after the father of Sri Mara. Rajaraja was succeeded by his son Rajendra I in 1014 A.D. He ruled jointly with his father for a few years. He also followed a policy of conquest and annexation adopted by his father and further raised the power and prestige of the Cholas. He followed the expansionist policy and made extensive con-quests in Ceylon.
 Rajendra Chola I the Emperor of the Chola dynasty conquered some territories of the Shailendra Dynasty in the 11th century. The devastation caused by Chola invasion of Srivijaya in 1025, marked the end of Shailendra family as the ruling dynasty in Sumatra. The last king of Shailendra dynasty — the Maharaja Sangrama Vijayatunggavarman — was imprisoned and taken as hostage