Medieval manuscripts which give a glimpse of life hundreds of years ago are to be to be given "new life" in an extensive conservation project.
The Castle Acre Processional and the Commonplace Book of Henry Appleyard are described as "extraordinary medieval treasures" by Norwich Castle Museum.
It said both are in fragile bindings but hopes the work will protect them.
The manuscripts will then go on public display when the renovated castle keep reopens next year.
The £13.5m Norwich Castle: Royal Palace Reborn project, on which construction began in August, will have more than 1,000 objects in a new permanent display telling the stories of medieval Norfolk.
Among them will be the Castle Acre Processional, a "rare and exquisite" 15th Century manuscript, likely to have been made and used by monks at Castle Acre Priory.
"Its leaves record the music and chants used for sacred ceremonies and feast days in the Christian calendar, clearly marking where, at what time and on which date the songs would be sung," the museum said.
Eventually, digital displays will invite visitors to turn its pages while listening to the recreated music of the monastic chants for the first time since the dissolution of the monasteries.
The Commonplace Book of Henry Appleyard, meanwhile, offers "a fascinating glimpse into the intellectual, moral and spiritual legacy of one Norfolk family in the reign of Queen Elizabeth I," the museum added.
It is believed the manuscript was begun around 1560 by Henry's father John Appleyard, owner of the manor - now a hotel - at Dunston, near Norwich.
Father and son penned information on a vast range of subjects including science, astronomy, the deeds of Roman emperors, and lists of mayors and sheriffs of Norwich.
Beautiful illustrations include delicate diagrams of the solar system and a "breathtaking" fold-out world map.
"It is a celebration of human curiosity, an ongoing quest for knowledge and the nature of our presence in the world - and, within it, the place of one Norfolk family," the museum said.
The conservation project was funded by a £20,350 grant from the National Manuscripts Conservation Trust, which will carry out the work.
"As well as being beautiful objects in their own right, these two manuscripts - one religious, one secular - give us a fascinating insight into the thoughts and lives of real people in medieval Norfolk," said Dr Tim Pestell, lead curator of the Royal Palace Reborn project.