Fortress Newark Under Siege 2015. Over the weekend of 3-4 May, enjoy an amazing weekend of re-enactments, displays, parades and living history bringing the dramatic times of the Civil Wars to life, featuring up to 1000 members of the Sealed Knot, English Civil War Society and History Re-enactment Workshop. The event is being arranged and coordinated by EventPlan Limited on behalf of the National Civil War Centre and Sherwood and Newark District Council.