The archaeological remains of ancient Pataliputra namely the Eighty pillared hall and Arogya Vihar are located at Kumrahar about six kms east of Patna railway station.Ancient literature refers Pataliputra by various names like Pataligrama, Patalipura, Kusumapura, Pushpapura or Kusumdhvaj. In 6th Century B.C. it was a small village where Buddha, sometime before his mahaparinirvana, had noticed a fort being constructed under the orders of King Ajatasatru of Rajagrih for defence of Magadh kingdom against the Lichchavi republic of Vaisali. Impressed by its strategic location king Udayin, son and successor of Ajatasatru, shifted the capital of Magadh from Rajgrih to Pataliputra in the middle of 5th Century B.C. For about next thousand years Pataliputra remained the capital of great Indian empires of Saisunaga, Nanda, Maurya, Sunga and Gupta dynasties. The place has also been an important centre of activity in the fields of education, commerce, art and religion. During Asoka's time the third Buddhist council was held here. Likewise Sthulabhadra, the eminent Jain ascetic had convened a council here during the time of Chandragupta Maurya.The first vivid account of Pataliputra including its municipal administration comes at about 300 B.C. from Megasthenese, the celebrated Greek ambassador at the court of Chandragupta Maurya, who mentions it as Palibothra in his book named Indica. According to his account the spread of the city was like a parallelogram, about 14 kms east-west along the river Ganges and 3 kms north-south. The circumference of the city was about 36 kms. The city was protected by massive timber palisades and further defended by a broad and deep moat which also served as a sewer of the city. Kautilya also in his book Arthasastra indicates wide rampart around the city. Remnants of the wooden palisades have been discovered during a series of excavations at Lohanipur, Bahadurpur, Sandalpur, Bulandibagh, Kumrahar and some other locations in Patna.