According to the Constitution of Bangladesh, Bangladeshi nationalism is formed by the unity and solidarity of the Bangladeshi people based on their cultural and linguistic heritage, and the revolutionary history of the Bangladesh Liberation War, through which the people successfully established the modern republic of Bangladesh.
The historic region of Bengal has been renowned for its rich cultural and linguistic heritage. The territorial unity and population growth of the region ran parallel with the development of the Bengali language under the patronage of the Turko-Afghan rulers of the Sultanate of Bengal. Besides developing Bengali, their next most outstanding contribution to the growth of Bengali identity was evolving of a polity based on Hindu-Muslim partnership and cooperation. The trend was further strengthened under the Mughal Empire. During the reign of the Nawabs of Bengal in the 18th century, which was a remarkable example of Hindu-Muslim unity, Bengal showed all the marks of the progressive growth towards the formation of a nation state in the European model taking shape after the fall of the Holy Roman Empire. With the defeat of Siraj-ud-Daula, the last independent Nawab of Bengal, by the British East India Company, Bengal lost its independence and its achievements during previous centuries in the fields of arts and crafts, manufactures and industries, education and administration were overturned under the impact of the colonial rule. However, gradually the British began fostering the European model of education in Bengal, the first province they captured in India. This led Bengal and especially Calcutta (present day Kolkata in West Bengal, India), the capital of British India during much of the Raj, to become the prime centre of modern culture, intellectual and scientific activities, politics and education in the Subcontinent. In what is described as the Bengal Renaissance, the introduction of Western culture, science and education led to a major transformation and development of Bengali society.