According to belief Gangaridai was a part of King Ashoka's Empire. During the rule of the Kushanas the major part of the state was ruled by three agents. Over a period of time these rulers refused to accept the suzerainty of the Kushanas and thereby became independent. This was followed by a period of uncertainty and turmoil. According to an inscription Simha Varman and his son Chandra Varman were the rulers of Bengal when the Guptas had come to power (319-20 A.D.). As per the Allahabad Stone Pillar inscription Samatata was a part of Samudragupta's kingdom. The inscription gives evidence that North Bengal was included within the Gupta Empire.
However during the decline of Gupta Empire it appears that Bengal was ruled by independent rulers which include Gopachandra, Dharmaditya and Samacharadeva according to the copperplate grants. In the middle of the sixth century A.D. Gauda gradually became a powerful state under the rule of King Sasanka. In course of time it developed to an empire that extended upto Kanya Kubja in the west and Ganjam in the south. King Sasanka was deposed by Bhaskara Varma. However he retrieved his position after Bhaskara's death in 650 A.D.
After a long period of chaos, the people of Bengal elected Gopala as their king who is the founder of Pala dynasty. Dharmapala, the successor of Gopala, is believed to have extended his empire from Kedar in the Himalaya up to Gokarna in Bombay. Deva Pala, son of Dharmapala established his control from the Himalaya Mountains to the Vindhyas. Deva Pala was succeeded by Vigraha Pala and thereafter succeeded by Narayana Pala. The Pala dynasty was attacked by the hill tribe Kamboja which was revolted by king Mahipala. Mahipala conquered east Bengal, Tirabhukti and the whole of Magadha. The Tamil king, Rajendra Chola advanced through Orissaand defeated Mahipala in 1023 A.D. The successors of Mahipala were weak which led to the revolt of the Kaivartas in north Bengal under the leadership of Divyoka. His successor, Bhima, was defeated by Ramapala who was the last known king of Pala dynasty.
Towards the end of the eleventh century the Varman dynasty came into power in east Bengal. Harivarmadeva was the most celebrated ruler of this dynasty. There is a probability that in the first half of the twelfth century, Vijayasena of the Sena dynasty gave a death-blow to the Varman dynasty. Vijayasena assumed power and founded the Sena dynasty. His son and successor, Ballala Sena devoted himself to social reforms and literary activities. His son, Laksmanasena annexed Mithila and Gaya to the kingdom of Bengal.
Towards the end of Laksmana's reign, Madhumathanadeva created an independent state on the eastern bank of the river Meghna. In the first half of the thirteenth century, the Deva dynasty ruled over that State. From 1227 to 1287A.D. fifteen rulers in succession occupied the throne of Bengal. Ten belonged to the Mamluk race among these fifteen who ruled Delhi. The Mamluk rule in Bengal was supplanted by the Tughlaq; Sultan Muhammad Bin Tughlaq conquered this State and it was under his rule. This regime gave way to the Iliyas Shahi rule.
Bengal had been ruled by Shahi and Afghan rulers. The Afghan rule was supplanted by Mughal rule also. In the sixteenth century, the Portuguese visited Bengal for business purposes and this made the English, French and Dutch visit Bengal. During the rule of Alivardi Khan Bengal was overrun by the Marathas. After the Battle of Plassey the whole of India came under the imperial control of the British.