The British Library has announced a £9m bid to save the 7th Century St Cuthbert Gospel - the earliest surviving European book - for the nation.
It follows a £4.5m National Heritage Memorial Fund grant towards that total.
The book, a copy of the Gospel of St John, was produced in northern England and buried with St Cuthbert before being rediscovered in 1104.
The manuscript, complete with original red leather binding, has been on loan to the library since 1979.
The Art Fund and the Garfield Weston philanthropic foundation have also pledged about £250,000 each towards the £9m total, with other organisations also making donations.
A further £2.75m is needed to acquire the gospel.
The book, formerly known as the Stonyhurst Gospel, was buried with the early English Christian leader on Lindisfarne, off the coast of Northumberland, in about 698.
It was found in St Cuthbert's coffin at Durham Cathedral in 1104 after it had been moved to escape Viking raids.
The library's chief executive, Dame Lynne Brindley, said the gospel was "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".
Christie's auction house approached the library - on behalf of the gospel's owners, the Society of Jesus (British Province) - to give it first option on buying the book.
If the British Library is successful in its campaign, the gospel will be displayed half of the time in the national library and the other half at the Unesco world heritage site 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."