The fifth Viking circular fortress has been unearthed in the fields of Vallø Estate, a manor house near the Zealand seaport of Køge. On September 6, The Telegraph reported that it is the first one to be discovered in over six decades.

Archaeologists from The Danish Castle Centre and Aarhus University were behind the discovery. As per them, the sites may have been built by Sweyn Forkbeard and the sites might have helped Forkbeard to become the first Danish King of England.

Lasse Sonne, a Viking historian at the University of Copenhagen, was of the view, "Although there were Vikings in other countries, these circular fortresses are unique to Denmark. Many have given up hope that there were many of them left".

The fortresses are quite old and are considered to be the facilities where warriors trained for a takeover of England. The recently found fortress is known as 'Vallo Borgring' and is quite similar to another found in the old market and railway town of Hobro.

As per archaeologists, the fortress is quite big and was built with heavy timbers and earthen embankments. It is said to be the third largest known fortress of its kind. The site is around 1,560-square-feet in diameter.

The fortress has not been completely unearthed. It follows a strict geometric pattern and has four gates present at the compass directions and a courtyard equally divided into four parts. During their raids on England, Vikings found old Roman army camps. There are chances that Vikings might have been inspired to come up with geometrical design after seeing those camps, believe historians.

The other four fortresses are said to have been constructed during the reign of Harald Bluetooth in the late 900s. There is a controversy over who actually built these fortresses.

Some historians said Bluetooth built these fortresses and others believe that the fortresses were constructed by his son, Sweyn Forkbeard. Sonne said the new discovery will help gain more information about Viking war and conflicts.