Ancient and classical Bengal

Stone age tools found in the Greater Bengal region indicate human habitation for over 20,000 years.Remnants of Copper Age settlements date back 4,000 years.

Mahasthangarh is the site of the oldest urban center in Bangladesh, dating back to the first millennium BCE

Mainamati is an archaeological site dating back to the first millennium CE

The Paharpur ruins, a UNESCO World Heritage Site.

Ancient Bengal was settled by Austroasiatics, Tibeto-Burmans, Dravidians and Indo-Aryans in consecutive waves of migration. Major urban settlements formed during the Iron Age in the middle of the first millennium BCE, when the Northern Black Polished Ware culture developed in the Indian subcontinent. In 1879, Sir Alexander Cunningham identified the archaeological ruins of Mahasthangarh as the ancient city of Pundranagara, the capital of the Pundra Kingdom mentioned in the Rigveda.
The Wari-Bateshwar ruins are regarded by archaeologists as the capital of an ancient janapada, one of the earliest city states in the subcontinent. An indigenous currency of silver punched marked coins dating between 600 BCE and 400 BCE has been found at the site. Excavations of glass beads suggest the city had trading links with Southeast Asia and the Roman world.
Greek and Roman records of the ancient Gangaridai Kingdom, which according to legend deterred the invasion of Alexander the Great, are linked to the fort city in Wari-Bateshwar. The site is also identified with the prosperous trading center of Souanagoura mentioned in Ptolemy's world map. Roman geographers noted the existence of a large and important seaport in southeastern Bengal, corresponding to the modern-day Chittagong region.
The legendary Vanga Kingdom is mentioned in the Indian epic Mahabharata covering the region of Bangladesh. It was described as a seafaring nation of South Asia. According to Sinhalese chronicles, the Bengali Prince Vijaya led a maritime expedition to Sri Lanka, conquering the island and establishing its first recorded kingdom. The Bengali people also embarked on overseas colonization in Southeast Asia, including in modern-day Malaysia and Indonesia.
Bengal was ruled by the Mauryan Empire in the 3rd and 2nd centuries BCE. With their bastions in the Bengal and Bihar regions (collectively known as Magadha), the Mauryans built the first geographically extensive Iron Age empire in Ancient India. They promoted Jainism and Buddhism. The empire reached its peak under emperor Ashoka. They were eventually succeeded by the Gupta Empire in the 3rd century. According to historian H. C. Roychowdhury, the Gupta dynasty originated in the Varendra region in Bangladesh, corresponding to the modern-day Rajshahi and Rangpur divisions.The Gupta era saw the invention of chess, the concept of zero, the theory of Earth orbiting the Sun, the study of solar and lunar eclipses and the flourishing of Sanskrit literature and drama.
In classical antiquity, Bengal was divided between various kingdoms. The Pala Empire stood out as the largest Bengali state established in ancient history, with an empire covering most of the north Indian subcontinent at its height in the 9th century. The Palas were devout Mahayana Buddhists. They strongly patronized art, architecture and education, giving rise to the Pala School of Painting and Sculptural Art, the Somapura Mahavihara and the universities of Nalanda and Vikramshila. The proto-Bengali language emerged under Pala rule. In the 11th-century, the resurgent Hindu Sena dynasty gained power. The Senas were staunch promoters of Brahmanical Hinduism and laid the foundation of Bengali Hinduism. They patronized their own school of Hindu art taking inspiration from their predecessors.The Senas consolidated the caste system in Bengal.
Bengal was also a junction of the Southwestern Silk Road.