Introduction:
The ruler of Bengal who was the first to assert independence was Murshid Quli Khan. He played a significant role in the political history of Bengal and initiated the process of centralization and consolidation of power in the region.

Background:
During the 17th and 18th centuries, Bengal was a wealthy and prosperous region under the Mughal Empire. However, the empire was in decline, and the central authority weakened. This created an opportunity for local rulers to assert their independence and establish their own rule.

Murshid Quli Khan:
Murshid Quli Khan was a Persian adventurer who arrived in Bengal in the late 17th century. He initially served as a Diwan (revenue officer) under the Mughal Empire but eventually rose to power and became the Nawab of Bengal in 1717.

Consolidation of Power:
After ascending to the position of Nawab, Murshid Quli Khan focused on consolidating his power and establishing his authority. He reformed the revenue system, introduced a new system of taxation, and brought stability to the region. His administrative reforms helped in increasing revenue and strengthening the economy.

Autonomy and Independence:
One of the significant steps taken by Murshid Quli Khan towards asserting independence was the establishment of an autonomous administration in Bengal. He negotiated with the Mughal Empire and obtained the grant of Diwani rights, which gave him control over revenue collection and administration in the region. This move effectively made Bengal an independent state, although it still nominally acknowledged Mughal sovereignty.

Legacy:
Murshid Quli Khan's assertion of independence laid the foundation for the independent Nawabi state of Bengal. His successors, including Alivardi Khan and Siraj-ud-daulah, further strengthened the state and played crucial roles in the political history of Bengal.

Conclusion:
Murshid Quli Khan, as the first Nawab of Bengal, was the ruler who first asserted independence from the declining Mughal Empire. Through his administrative reforms and negotiations with the empire, he established an autonomous administration and effectively made Bengal an independent state. His actions had a significant impact on the political history of the region and set the stage for the subsequent rulers of Bengal.