<P> The city of Pataliputra was formed by fortification of a village by Haryanka ruler Ajatashatru, son of Bimbisara . </P> <P> Its central location in north eastern India led rulers of successive dynasties to base their administrative capital here, from the Nandas, Mauryans, Shungas and the Guptas down to the Palas . Situated at the confluence of the Ganges, Gandhaka and Son rivers, Pataliputra formed a "water fort, or jaldurga". Its position helped it dominate the riverine trade of the Indo - Gangetic plains during Magadha's early imperial period . It was a great centre of trade and commerce and attracted merchants and intellectuals, such as the famed Chanakya, from all over India . </P> <P> Two important early Buddhist councils are recorded in early Buddhist texts as being held here, the First Buddhist council immediately following the death of the Buddha and the Second Buddhist council in the reign of Ashoka . Jain and Brahmanical sources identify Udayabhadra, son of Ajatashatru, as the king who first established Pataliputra as the capital of Magadha . </P> <P> During the reign of Emperor Ashoka in the 3rd century BCE, it was one of the world's largest cities, with a population of 150,000--400,000 . The city is estimated to have had a surface of 25.5 square kilometers, and a circumference of 33.8 kilometers, and was in the shape of a parallelogram and had 64 gates (that is, approximately one gate every 500 meters). Pataliputra reached the pinnacle of prosperity when it was the capital of the great Mauryan Emperors, Chandragupta Maurya and Ashoka . The city prospered under the Mauryas and a Greek ambassador, Megasthenes, resided there and left a detailed account of its splendour, referring to it as "Palibothra": </P>

Who made patliputra the first capital of magadh