During the English Civil War, Newark was known as the 'Key to the North' because of its great strategic importance. The River Trent, and two vital communication routes - the Great North Road and the Fosse Way - all met here. Newark had provided staunch support for King Charles I and the royalists, but Parliament was determined to take it. After two failed sieges, they were back in 1645 for a third go. This time they meant business. The team starts their dig at Shelford, the site of an early battle in the siege. They discover two medieval buildings - one which was standing at the time of the battle and the other they believe was a church buried beneath the defensive rampart.