The Oxford University and Vatican libraries are to jointly digitise 1.5m pages of ancient texts and make them available free online.
The libraries said the digitised collections will centre on three subject areas: Greek manuscripts, 15th-century printed books and Hebrew manuscripts and early printed books.
The areas have been chosen for the strength of the collections in both libraries and their importance for scholarship in their respective fields.
With approximately two-thirds of the material coming from the Vatican and the remainder from Oxford University's Bodleian libraries, the digitisation effort will also benefit scholars by uniting materials that have been dispersed between the collections for centuries.
"Transforming these ancient texts and images into digital form helps transcend the limitations of time and space which have in the past restricted access to knowledge," Sarah Thomas, director of the Bodleian Libraries, said on Thursday.
"Scholars will be able to interrogate these documents in fresh approaches as a result of their online availability."
The initiative has been made possible by a £2m award from the Polonsky Foundation.
"The service to humanity which the Vatican library has accomplished over almost six centuries, by preserving its cultural treasures and making them available to readers, finds here a new avenue which confirms and amplifies its universal vocation through the use of new tools, thanks to the generosity of the Polonsky Foundation and to the sharing of expertise with the Bodleian libraries," Holy See librarian Cardinal Raffaele Farina said.