B.B.D. Bagh (or Dalhousie Square as it was formerly known) was created as the center of the British East India Company's trading post along the banks of the Hooghly River. Between the river and the tank (now known as Lal Dighi), lay the original Fort William. In the summer of 1756, Nawab Siraj ud-Daulah of Bengal, Bihar and Orissa launched an attack on the British town for the company's decision to strengthen the fortifications around it. The survivors of the attack were sent to a garrison within the fort which spurred an incident infamously known as the Black Hole of Calcutta. The British soon retook the city after the Nawab retreated from the forces of Robert Clive. Within a year, the British East India Company's forces had taken all of Bengal and Calcutta, along with the square, was established as the commercial and political center of British-occupied India.