A community dig has shed new light on a castle which for centuries was in the front line of the conflict between England and Scotland.
It has shown that Wark Castle on the Northumberland side of the River Tweed was more of a heavyweight prospect than previously believed.
The excavations are the latest in a series by the Flodden 500 Archaeological project.
The venture began in 2009 with a grant from English Heritage in the run-up to last year’s marking of the 500th anniversary of the Battle of Flodden.
It has led to the setting up of the Till Valley Archaeology Group, which now has more than 100 members.
The digs are part of the Flodden 1513 programme to highlight the anniversary, and are set to continue.
Wark Castle has been the current focus of the dig volunteers.
It was captured by the Scottish King James IV in August 1513, prior to the meeting of his army with the English at Flodden in the September.
The 10-day dig tackled a field adjacent to the castle site, and uncovered the remains of a massive defensive wall five metres thick. In addition evidence was revealed of a second outer bailey area of the castle.
“We have demonstrated that the castle is twice the size it has been supposed to have been,” said Chris Burgess, Flodden 1513 archaeology manager.
“This helps us to understand why the castle was considered to be so important.”
A dig by the project last year at Norham Castle on the Tweed also showed that it occupied a bigger area than was thought.
Other finds at Wark included 13th and 14th Century pottery, an armour-piercing arrowhead and bones from butchered livestock.
Wark Castle was built in the 12th Century and suffered several sieges and changing of hands between the English and the Scots.
King Edward I and Edward III are believed to have stayed at the castle, and King Henry VI and his Queen Margaret sought refuge there after the Battle of Towton in 1461 in the War of the Roses. In 1513, James IV of Scotland failed to take Norham Castle but did manage to capture Wark.
“The Scots did not want to bypass the castles because of the danger of the garrisons later attacking the supply lines of the Scottish army,” said Chris.
After the English victory at Flodden, King Henry VIII turned Wark into an artillery fortification.
“It marked a change in thinking, No longer was the castle a base from which some powerful individual ruled but instead it became a government fortification to stop the Scots crossing the River Tweed,” said Chris.
Later this year the volunteer diggers will return to Flodden Hill for a fifth season of digging.
The site is believed to have been the Scottish camp before the Battle of Flodden.
The previous excavations suggest that the Scots built their earthwork defences on top of an existing Iron Age hill fort.
The project also plans digs north of the Tweed at Ladykirk, from where James IV launched his attack on Norham Castle and Ellem Kirk, where the Scots army gathered in 1513 before crossing into England.