Lincoln Castle, built by William the Conqueror in 1068 on the site of a Roman fortress, stands as one of England's best-preserved Norman castles. Unique as one of only two castles with two mottes (mounds), it features a complete medieval wall walk offering 360-degree views. The Victorian Prison, operational from 1787 to 1878, represents a complete separate system prison with the world's only surviving prison chapel of its type. The castle houses one of only four surviving original 1215 Magna Carta copies in a purpose-built underground vault. Still functioning as a Crown Court, Lincoln Castle uniquely combines nearly 1000 years of legal and penal history in one remarkable site. **Filming Scenes:** Lincoln Castle's Victorian Prison portrayed York Prison where John Bates was wrongfully imprisoned for murdering his ex-wife Vera in Series 3. The authentic Victorian cells, with their heavy doors and sparse furnishings, provided the perfect backdrop for Bates's unjust incarceration. The prison's separate system design, where prisoners were kept in solitary confinement, emphasized Bates's isolation from Anna and Downton. The chapel's unique individual prisoner enclosures, designed to prevent inmates from seeing each other, appeared in prison service scenes. The historically accurate setting, having actually operated as a prison during the Victorian era, added gravitas to this dramatic storyline.