Kasimbazar a great commercial centre on the river Bhagirathi during the seventeenth century and developed into a flourishing silk-town in the late eighteenth. In the Mughal imperial Trunk Roads system Kasimbazar was considered as a nerve centre because of its linkage with rajmahal, Bhagalpur and Patna in the west and Dhaka in the east. james rennel has described its communicational link with other Bengal marts in his Description of the Roads in Bengal and Bihar (London 1779).
Kasimbazar was well known in the commercial world as an international mart for silk, as Bhagwangola was for grain. Most European traders, particularly the dutch and the english, had their agencies in Kasimbazar. In the Kasimbazar silk-trade, the Dutch were dominant till mid eighteenth century while the British began to dominate from the early 1750s. Throughout eighteenth century Kasimbazar was the biggest mart in eastern India for silk and silk piece goods. It was also a great weaving centre where great amount of raw silk and cotton materials were manufactured and exported to various parts of Asia and Europe. Besides Calcutta, the next bastion of power for the English east india company was Kasimbazar. One of the causes contributing to the battle of palashi was an attack on the English factory by sirajuddaula. [Sirajul Islam]