Princess Anne has officially reopened Lincoln Castle after a multi-million pound refurbishment.
The £22m works, which finished in March, included the construction of a vault for the city's copy of Magna Carta.
A new exhibition in the Victorian prison will display objects found in the grounds during the renovation.
Exhibits include a facial reconstruction of a Saxon man, whose skeleton was found in the grounds.
There will also be a bronze Roman eagle and a limestone sarcophagus on show.
Antony Lee, of Lincoln Museum, said some exhibits dated back 2,000 years.
"What's nice is we can show them very close to where they were excavated," he said.
The reopening ceremony was open only to winners of a ballot.
Princess Anne entered the grand gate of the East Wing before greeting the assembled crowd and unveiling the plaque.
She also walked the castle walls, visited the Magna Carta vault and the Victoria Prison and is set to visit Boston Stump for a service of dedication.