Genealogy in Tanjavur, India

Hi,

I just found out that one of my ancestors was from Umerpatah, Tanjore, India, near MAdras. This information comes from Mauritius where my ancestor immigrated to in 1850.

Where can I find more about him? Please if you have any idea to whom I have to talk with, or where to go online, please tell me!

Thanks for your time

Carolina