The gospels used revolutionary printing techniques
Researchers have found a possible link between the Lindisfarne gospels and another celebrated early British text, proving they may have been written at the same time in the same region.
The gospels are now thought to have been written at the same time as Bede's Ecclesiastical History of the English people, according to the British Library.
The complex and lavishly decorated gospels are widely recognised as the pinnacle of Anglo Saxon cultural achievement.
They were thought to have been written by Eadfrith, the bishop of Lindisfarne, in 698 AD, as a tribute to St Cuthbert.
But the date has now been revised to around the year 720 AD.
It would put the book's completion at the same time the Venerable Bede was compiling his work on the British people.
Dr Michelle Brown, the British Library's curator of illuminated manuscripts, told BBC News Online said the manuscript was seen as "creating an identity for Britain.
You have to look at the bigger picture and what was going on in the world at the time
Dr Michelle Brown, British Library's curator of illuminated manuscripts
"It makes the transition from the Greco-Roman world to a new identity for Britain, and a very international one at that," she said.
Dr Brown said the gospels and Bede's work symbolised the creation of the building blocks of modern British society.
She said the earlier accepted date had ignored a lot of archaeological and historical detail that related to Eadfrith's work.
She said: "When you're looking at something like this, you have to look at the bigger picture and what was going on in the world at the time. Then we can get out our microscopes - and our 'intellectual microscopes' - and actually look at physically dating the book."
They used a non-destructive laser to analyse the books' pigments to help guess its age.
Dr Brown said Eadfrith has used revolutionary techniques when he created the gospels.
She said there was evidence he had invented lead pencils - 300 years before they were widely used - in making the Lindisfarne gospels.
"He also invented the lightbox," she said. "He used the same technique as modern cartoonist - putting emulsion on the opposite side so he did not cover fine detail."
Dr Brown said he had also used come up with an enormous range of colours using only six local materials, and the colours were so varied "even Photoshop would have difficulty matching them".
The gospels are on show at the British Library from Friday until 28 September.
Copies of the gospels have been created. They will be unveiled on Friday at Durham Cathedral and Saturday at Holy Island, the site of Lindisfarne Monastery.