Why an exhibition here? Well, several knights were imprisoned down below in the dungeons of the castle after the order was crushed by order of Pope Clement. The English dragged their feet initially in suppressing the Templars but then got on with the job. The poor knights were rounded up, locked away and tortured to confess to various trumped up charges.
Intriguingly, the imprisoned Templars scrawled religious symbols on the walls – something they seemed to have done wherever they were imprisoned. For example, Gisors in France.
The dungeons were incredibly grim and disease ridden. Many of those incarcerated would have survived a matter of days and death might have been a sweet release. Food was basic and disgusting while the only drink would have been ale brewed in the castle. That at least might have eased your suffering.
Like many Norman castles, it started out as a wooden construction commissioned by Alexander, Bishop of Lincoln. Later on, a stone fortress replaced the wood. As happened to quite a few medieval castles, it was partially demolished after the English Civil War in the 17th century to stop royalists threatening the newly founded republic of Oliver Cromwell.