After the Mughal raid on Hooghly, Job Charnock, a company agent, started negotiations with the Mughals so as to return to a place called Sutanuti.  

• Charnock signed a treaty with the Mughals in February 1690, and returned to Sutanuti in August 1690.  

• Thus, an English factory was established on February 10, 1691, the day an imperial farman was issued permitting the English to “continue contentedly their trade in Bengal” on payment of Rs 3,000 a year in lieu of all dues. 
• A zamindar in Bardhaman district, Sobha Singh, rebelled; subsequently giving the English the pretext they were looking for, to fortify their settlement at Sutanuti in 1696.  
• In 1698, the English succeeded in getting the permission to buy the zamindari of the three villages of Sutanuti, Gobindapur and Kalikata (Kalighat) from their owners on payment of Rs 1,200.  
• The fortified settlement was named Fort William in the year 1700 when it also became the seat of the eastern presidency (Calcutta) with Sir Charles Eyre as its first president. 

Source: Spectrum’s A Brief History of Modern India.