A team of archaeologists of the Archaelogical Survey of India have discovered the main entrance of the ancient Nalanda university in Bihar.

P K Mishra, superintending archaelogist of the ASI, Patna circle, told rediff.com on Monday that the main entrance was discovered at Badagaon near the standing ruins of the university.

"It was a big discovery to know more about the ancient university. Till date the archaeologists were in the dark about its main entrance," he said.

According to Mishra, Badagaon is also known as Paragan, a nearly 1,200-feet-high mound popularly known as Dhamma Khand.

It is spread over nearly 20 acres of land. The location of the mound in the extreme north of the ancient site indicated that it was the entrance of the university.

The archaeologists have also discovered a wall under the mound.

ASI Patna circle is preparing a project report for excavation of the mound.

Early this month, the ASI had invited scientists of the Indian Space Research Organisation for radar mapping to explore unexplored archaelogical structures in and around the ruins of the ancient university.

Mishra said the radar mapping would help in finding archaelogical structures that were yet to be explored around the ancient Nalanda University.

"Radar photography has proved fruitful across the world for exploration of archaeological structures," Mishra said.

The Chinese scholar Hieun Tsang who visited Nalanda university stated in his writing that the university was spread over an area of 16 kilometres. Till now hardly 1.6 square kilometres of the ancient university has been excavated.

"Large parts of the ancient university remain to be excavated," Mishra said.

Hieun Tsang stayed here in the 7th century AD and left detailed descriptions of the excellence of the education system and the purity of monastic life practised in the ancient university.

Nalanda, the oldest university in the world, was founded in 5th century AD.