The Queen and Duke of Edinburgh were shown around a £19 million state-of-the-art resource centre.
Her Majesty officially opened The Keep, near Falmer, which will provide a home for archives and historical resources of East Sussex and Brighton and Hove.
Archivists showed the royal delegation maps of Sussex from 179, historic pictures of Eastbourne before it became a resort.
- 'Our beautiful girl': Parents pay tribute to suspected murder victim
- Boyfriend pays tribute to suspected murder victim Shana Grice as police watchdog notified
- Mother dies suddenly just seven weeks after birth of baby
- Concern for missing Samantha Barrett, 43
- Five men who died at Camber Sands now named
Other achived included photos of Brighton Carnival stretching along Madeira Drive and its oldest document, Battle Abbey Charter, from 1101.
Senior Archivist Chris Whittick said: “They both showed a great interest in what he had shown them and they made most perceptive comments.
“We tried to select documents that would be of interest but not too personal. I think we got the right balance.”
Around two hundred royal watchers waited at Woollards Field, Moulsecoomb, for the royal cavalcade to arrive.