Tiruchchirappalli was an important regional capital of the Pallava, Chola, and Vijayanagar dynasties from the 7th to the 17th century. Its rock fortress, dominating the city, was the scene of bitter fighting between Muslim, Maratha, British, and French troops from the 17th to the 19th century. The city is now an industrial centre that has heavy electrical, thermal boiler, and locomotive construction workshops alongside traditional cotton hand-weaving and cigar-rolling cottage industries. Synthetic diamonds are manufactured as well. The city is the site of Bharathidasan University (1982). The surrounding Kaveri River valley is one of the best rice-growing regions in the state and also produces sugarcane and betel. Pop. (2001) city, 752,066; urban agglom., 866,354.