The British first built Fort William in the middle of a dense jungle. When disagreements led the local Bengali ruler, Siraj ud-Daula, to attack and destroy it, the British response was a quick and decisive battle led by Robert Clive. The Battle of Plassey (some 160 km [100 miles] north of town), transformed the British from traders into a ruling presence in 1757—after it, the forest was cut down in order to provide a clear line for cannon fire in case of attack. It's really from the year 1757 that modern Kolkata traces its history, and from the impenetrable Fort William (completed in 1773) that the city began its explosive growth.
Starting about 1 km (½ mile) north of the fort, central Kolkata became the commercial and political heart of the city. It was here that the British conducted business, and here that they built their stately homes. The immense area cleared for British cannons is now Kolkata's 3-square-km (2-square-mile) park, the Maidan, and central Kolkata now goes beyond the Maidan to B. B. D. Bagh square and most of the commercial and residential areas to the east of the giant park.