In book 'History of India' by Hermann Kulke and Dietmar Rothermund , following lines are of much importance as they describe what Megasthenes the Seleucid envoy to Mauryans said about capital itself. "Two parts of his report have attracted special attention: his description of the imperial capital, Pataliputra, and his account of the seven strata of Indian society which he observed there. He reported that Pataliputra was fortified with palisades. This fortification was shaped like a parallelogram measuring about 9 miles in length and about l.5 miles in breadth and it had 570 towers and 64 gates. The circumference of Pataliputra was about 21 miles and thus this city was about twice as large as Rome under Emperor Marcus Aurelius. If this report is true, Pataliputra must have been the largest city of the ancient world" There is simply no reason to distrust his account when it is so accurate about city with care about gates and towers, the only reason is 'Rome was largest' prejudice. Pataliputra was not some Rome or Vijaynagar situated far from rivers flooding their surrounding areas, much of Mauryan city is now under deep bed of river Ganga so archaeological excavation can not help much. Even then Raymond Allchin did find timber walls of city( which proves correctness of Megasthenes) covering an area upto 2200 hectares and Raymond does say that walls are partly excavated and will never be fully known about. As per Megasthenes , area was around 3400 hectares. Given that Mauryans controlled all lands from Karnataka to Kabul , it is not surprising. Also, Kannauj capital of Harshavardhana's area was around 1000-1100 hectares so there is nothing inconsistent about this size of Pataliputra. Tangs had their capital city Changan as large as 8000 hectares. Many expressed doubts about Megasthenes account but as the book says "But the German Indologist D. Schlingloff has shown that the distances between the towers or between a tower and the next gate as derived from Megasthenesâ€™ account closely correspond to the distance prescribed for this kind of fortification in Kautalyaâ€™s Arthashastra (i.e. 54 yards)." Megasthenes mention 570 towers which means distance between two towers was around 54 yards so 570 towers in a parallelogram give us same area. Greek writer Arrian has described Mauryan palace as excelling in splendour royal palaces of Susa and Ecbatana. Interestingly, we have corraboration of same from Chinese traveller Fa Xian who visited Pataliputra in early fifth century and described palace as something which could not be created by humans alone. So archaeology, Megasthenes and Indian accounts all show that Pataliputra was larger than Rome. Rome had an area of around 1700 hectares under Marcus Aurelius.