Before Rome was a city, there was Pataliputra. The Greek ambassador Megasthenes visited it in the 3rd century BCE and declared it the largest, most magnificent city on Earth. It was the capital of the Mauryan Empire — the first to unite the Indian subcontinent — governed by Ashoka the Great, whose Chakra sits at the centre of India's flag to this day.

Bihar is where the Buddha attained enlightenment. Where Mahavira founded Jainism. Where Chanakya wrote the world's first systematic treatise on economics and statecraft. Where Aryabhata calculated the value of pi and proposed that the Earth rotates on its axis — a thousand years before Europe caught up. Where Nalanda University educated 10,000 students from across Asia for seven centuries, until it was burned in 1193 CE and its library took three months to stop burning.

Ray takes you through the full sweep of Bihar's extraordinary history — from the Licchavi republic of Vaishali, one of the world's earliest democratic polities, through the Mauryan and Gupta golden ages, Sher Shah Suri who gave India the rupee and the Grand Trunk Road, to Gandhi's first Satyagraha in Champaran and JP Narayan's Total Revolution.

We meet Bismillah Khan, whose shehnai played at India's first Independence Day. We meet Ramdhari Singh Dinkar, whose poetry made Hindi roar. We meet Vidyapati, who gave Maithili its classical voice five centuries ago. And we eat litti chokha — the smoky, stuffed wheat ball that Sher Shah's army marched on, and that a homesick Bihari makes first whenever they miss home.

We stand at Bodh Gaya at dawn. We walk through the ruins of Nalanda. We wade into the Ganges at sunset for Chhath Puja — the most democratic festival in India, with no priest, no temple, just a devotee, the water, and the sun.

New episodes every Tuesday at 7pm. Next week — Chhattisgarh.