Idrakpur, now Munshiganj was a strategically very significant point as it was the junction of a number of rivers including Meghna River, Shitalakshya River, Ichhamati River and Dhaleshwari River. The fort was built on the bank of the junction of Ichhamati River and Meghna River.
The Portuguese and Magh pirates used this point to move forward to Dhaka through Shitalakshya River. On their way they to Dhaka they used to loot other important cities like Sonargaon and Bikrampur.
Mir Jumla II was determined to protect Dhaka and eager to develop the wealthy area Bikrampur. So, he came up with a triangular defense strategy to protect the cities from the Portuguese pirates.
Idrakpur Fort was the center of his strategy. The erection of the fort was intended to check the advance of the Magh and Portuguese pirates proceeding towards the Mughal capital city of Dhaka. The fort was also used as the naval base of the naval fleet of 200 frigates under Mughal admiral Abul Hossain.
According to the strategy, whenever the pirates made an attempt to advance to Dhaka the Mughal soldiers would be ordered to start firing mortars both from the cannons of their 200 battleships and from the Idrakpur Fort leaving the pirates with no options but to retreat or die on the rivers.
However, if any of the pirate ships survived the initial attack and tried to advance to Dhaka the Sonakanda Fort and the Hajiganj Fort, situated on the eastern and western bank of Shitalakshya River respectively, would start throwing round-shots to those ships and vessels and sink all the pirate ships on the river. It was probably built in about 1660 A.D.
Mughals took over the control of the Bengal in 1574 AD after defeating Daud Khan Karrani. Mughals exercised a progressive rule in Bengal. Bengal was then a very wealthy province and was frequently attacked by the pirates.
The Mughal Empire was then locked into a civil war regarding the succession of Emperor Shah Jahan. Shah Shuja, the second son of Shah Jahan and the Subahdar of Bengal, led a campaign to Agra in order to take over the throne. Aurangzeb, after his accession to the throne wanted to appoint a man with high skills in naval warfare as the river-oriented Bengal was the strong hold of Shah Shuja. So he entrusted Mir Muhammad Saeed Ardestani alias Mir Jumla II who was a successful trader in maritime trades in first life, to deal with Shah Shuja.
Mir Jumla II rushed to the Bengal compelling Shah Shuja to retreat. Later, Mir Jumla II was appointed as the Subahdar or the governor of the then Bengal province in 1660.
Mir Jumla was aware of the pirates who used to run a campaign of terror in the important cities of Bengal. After his appointment as the Subahdar, he shifted the capital of Bengal to Dhaka from Rajmahal. In a quest to protect the capital Dhaka from the pirates, Mir Jumla II developed a triangular defense strategy and decided to build up three river forts near Dhaka. One of these three forts is Idrakpur Fort of Munshiganj.
