Chola Territories c. 905 CE
Pallava Civil War 
When Nandivarman died in 869 CE differences arose between Nripatunga and his stepbrother Aparajita, probably owing to the latter’s ambition to rule the kingdom on his own right. Both sides looked for allies. Nripatunga continued to have Varaguna Pandya by his side while Aparajita allied with the Ganga king Prithvipathi I and with Aditya Chola I.
The rival armies met at Thirupurambiyam near Kumbakonam c. 885 CE. The armies of Pandyas and Nripatunga Pallava were routed by Aparajita Pallava and Aditya I Chola.
Aditya I’s ascendancy 
Although the victor of the Thirupurambiyam battle was Aparajita, the real gains went to Aditya I Chola. This battle ensured the end of Pandya power in the south. Pandya Varagunavarman renounced his throne and turned an ascetic. The grateful Aparajita not only allowed Aditya I Chola to keep the territories won by Vijayalaya Chola, but also to add new territories from the defeated Pandyas.
Aditya I’s invasion of the Pallava Country 
During 903 CE, the 32nd year of his reign, Aditya I Chola, not satisfied with his subordinate position, planned and carried out an attack on his erstwhile overlord, the Pallava king Aparajita. In the battle that ensued, Aditya pounced upon Aparajita when he was mounted on an elephant and killed him. That spelt the end of the Pallava rule in Tondaimandalam (north Tamil Nadu) and the whole of the Pallava kingdom now became Chola territory. This spelt the effective end of the once great Pallava empire in the history of South India.
The conquest of the Tondaimandalam earned for Aditya I the epithet "Tondainadu pavina Rajakesarivarman" (தொண்டைநாடு பாவின இராசகேசரிவர்மன்) - "Rajakesarivarman who overran Tondainadu".
The Conquest of Kongu 
Aditya I next conquered the Kongu country in the south west of Tamil Nadu, perhaps from the Pandya king Viranarayana.
Relations with the Cheras 
Friendly relations appear to have existed between the Cheras and the Cholas in the reign of Aditya I. The Chera contemporary Sthanu Ravi is stated in inscriptions to have received royal honours from Aditya. AdityaI ’s son, Parantaka I married a daughter of Sthanu Ravi.
Aditya’s contributions to Hinduism 
Aditya I is claimed to have built a number of temples for Siva along the banks of the Kaveri. The Kanyakumari inscription gives us the information that Aditya I was also known by the surname Kodandarama. There is a temple near the town of Tondaimanarrur called Kodandaramesvara, also mentioned in its inscriptions by the name Adityesvara. This seems to have been built by Aditya I.He also revised Annamalaiyar sanctum in tiruvannamalai during 872-900.
Death and succession 
In an inscription Aditya is distinguished by the epithet "Tondaimanarrur tunjina udaiyar (தொண்ைடமானரூர் துஞ்சின உைடயார்)- "the king who died at Tondaimanarrur". Aditya I died in 907 CE at Tondaimanarrur. His son Parantaka I built a Siva temple over his ashes. Aditya I was survived by his queens Ilangon Pichchi and Vayiri Akkan alias Tribhuvana Madeviyar. Besides these two queens Aditya I also had a mistress named Nangai Sattaperumanar as evidenced from an inscription.
Aditya I had a long and victorious reign during which he laid the foundation of the future greatness of the Chola empire.
- Tamil And Sanskrit Inscriptions Chiefly Collected In 1886 - 87, E. Hultzsch, Ph.D., Published by Archaeological Survey of India, New Delhi
- Nilakanta Sastri, K. A. (1935). The CōĻas, University of Madras, Madras (Reprinted 1984).
- Nilakanta Sastri, K. A. (1955). A History of South India, OUP, New Delhi (Reprinted 2002).
Parantaka Chola I