Thanjavur was the royal city of the cholas, Nayaks and the Mahrattas. Thanjavur derives its name from Tanjan-an asura (giant), who according to local legend devastated the neighbourhood and was killed by Sri Anandavalli Amman and Vishnu, Sri Neelamegapperumal. Tanjan's last request that the city might be named after him was granted.

Chola, Chera and Pandya kings were ruling Tamizhagam even before Mahabharat period. Chola kingdom was leading and patronizing literature, art, science and religion than the other two kingdoms. The capital city of Chola was always changing. Thiruvarur was the capital during Manuneethi Cholan. Kaveripoompattinam was the capital after that and was an important harbour. Uraiyur, Pazhaiyarai, Thanjavur and Gangaikonda Cholapuram used to be the capitals of Chola Kingdom. Its been believed from the Epics that many Chola kings were ruling from Thanjavur even before Karikal Cholan.

Historian believe that Thanjavur was captured by Vijayalaya Cholan (AD 846-880) from Perumpidugu Muttaraiyan. From then till Rajaraja Cholan, Thanjavur was flourishing. Chola kings were ruling till 13th Century AD with Thanjavur as their capital. Rajendra Cholan, Rajarajan's son moved the Chola capital to Gangaikonda Cholapuram. After that Chola Kingdom was declining and the Pandya Kings captured Thanjavur.

Vijayanagar Kings captured in 14th Century AD. Sevvappa Nayak (AD 1549-1572), an erstwhile viceroy of the Vijayanager empire assumed independence and founded the dynasty of the Thanjavur Nayaks. Thanjavur remained the capital of the Nayaks for the next one hundred and twenty five years till Vijayaraghava - the last prince of the line - perished in a tragic but a heroic war with Chokkanatha of Madurai in 1662 AD. His General Alagiri ruled for another fourteen years. The claim to the Nayak throne through Sengamaladas, the infant son of Vijayaraghava brought on the scene the Bijapur King and his general.

General Venkaji alias Ekoji, was the half brother of Sivaji the Great. He defeated Alagiri and seized the throne in 1676 because of the dissensions in Nayaks. Mahrattas kings for one hundred and seventy-nine year ruled with Thanjavur as the capital. The English first interfered in 1749 AD with a view to the restoration of deposed King, Saiyaji.

In 1758 AD French attacked but was retaken by British in 1773 AD. Thanjavur became a protected state under the East India Company. In 1799 AD Thanjavur became a British principality and its ruler Sarafoji II was given the fort of Thanjavur and an area outside it. Sivaji, his successor died in 1855 AD without an heir and after him Thanjavur passed directly under British. Its accquisition never costing the British the life of a single soldier, in the same manner as the Mahrattas had taken the country previously from the Nayaks.

Of the various rulers of Thanjavur, the Cholas seem to have left in the Great temple of Sri Bragatheeswara a striking relic of their genius. The temple stands tall within the small fort, commonly called the Sivaganga Fort, ascribed to the Sevvappa Nayak and the big fort which encircles the city and the palace was built by Vijayaraghava the last. These two forts could the renovations of the earlier chola fortifications.