The East India Company acquired a charter from the ruler of England, Queen Elizabeth I in the year1600 granting it the sole right to trade with the East without competition from other British traders.
But that royal charter could not stop other European powers such as the Portuguese, Dutch, and French. Also, all those European companies wanted to buy the same things from India that are fine qualities of cloth and spices.
Soon, profits fell as the competition grew bigger and the European trading companies started building forts and fighting each other.
More conflicts arose because of more business with the Indian rulers, and it became difficult for the European traders to keep their business separate form Indian politics.
All these led to the 1757 Battle of Plassey.
After the Battle of Plassey, the original nawabs of Bengal were forced to give land and vast sums of money as personal gifts to Company officials.