A multimillion-pound fundraising campaign has begun to buy a 7th Century book produced in Northumberland and valued at £9m.
The St Cuthbert Gospel is the earliest surviving intact European book, created on the island of Lindisfarne, off the Northumberland coast, in around 698 AD.
It lay buried in the coffin of St Cuthbert until moved to Durham Cathedral hundreds of years later.
The British Library wants to save the book for the nation.
The manuscript, a copy of the Gospel of St John, has been described as a "beautifully-preserved window" on the Anglo-Saxon period.
It is currently owned by the British Province of the Society of Jesus, which has offered the British Library first option to acquire the work.
The saint's coffin was moved off the island to escape Viking raiders and taken to Durham, where the book was found when the coffin was opened at the cathedral in 1104.
Its original red leather binding survives today.
Dame Lynne Brindley, the library's chief executive, said: "The St Cuthbert Gospel is an almost miraculous survival from the Anglo-Saxon period, a beautifully-preserved window into a rich, sophisticated culture that flourished some four centuries before the Norman Conquest."
The National Heritage Memorial Fund has already pledged half the money needed - £4.5m - and another £500,000 is being provided by other groups.
The gospel has been on loan to the library, in London, since 1979 but if the bid is successful, it will spend half the year on show in Durham.
The Very Reverend Michael Sadgrove, Dean of Durham, said: "This wonderful book links us directly to Saxon Christianity of the north of England, and to the north's best-loved saint, Cuthbert himself.
"Durham Cathedral owes its very existence to him and we prize not only his memory, but also the treasures associated with him.
"Like the Lindisfarne Gospel Book, the Cuthbert Gospel speaks powerfully about Northumbria's golden age, whose spiritual vision, intellectual energy and artistic achievement continue to inspire us today."
A spokesman for the British Province of the Society of Jesus, said: "We are delighted that this rare text is likely to be fittingly housed, and congratulate the library on a successful start to the fundraising campaign."