Skilled conservation specialists are currently engaged in the meticulous restoration of several ancient Irish documents, such as a medieval parish registry.

The 650-year-old ecclesiastical register currently being restored once belonged to Milo Sweteman, the archbishop of Armagh, Ireland from 1361 to 1380.

The Public Records Office of Northern Ireland is working painstakingly to restore the delicate pages as part of an initiative to preserve some of the country’s most important historical texts. Many of these texts were destroyed or stolen over the many centuries Ireland was under foreign occupation or rule, primarily by the British from the 12th to the 20th century.

Documents like the ecclesiastical registers are particularly key to the PRONI’s endeavors because they contain copies or drafts of documents created by the archbishops’ administration work, including legal papers, official letters, correspondence, receipts, and wills.

Conservation work on the register of archbishop John Swayne, dated from 1418 to 1438, is already complete and has been digitized with a translated summary.

Many documents that would help trace back generations to Ireland were destroyed when the Public Record Office of Ireland in Dublin was set on fire in June 1922 at the beginning of the Irish Civil War, which lasted only nine months and saw the establishment of the Irish Free State comprised of all but the six counties that came to be known as Northern Ireland.

The work to repair Sweteman’s register will aim to fix the wear and tear that resulted from conservation efforts at the start of the 20th century when someone placed tracing paper on top of the pages in an effort to preserve them. The tracing paper was acidic and, instead, accelerated the corrosion of the ink and paper, doing more harm than good, The Guardian reported.

The PRONI team are working to remove the tracing paper using specialized gel. When they finish up, they plan to put the pages through a low-pressure washing process before using the same materials they used to mend Swayne’s register — Japanese kozo paper and wheat starch paste — to finish off the repairs.

The same is being done to a third register that belonged to archbishop Nicholas Fleming between 1400 and 1418.

Sarah Graham, the head conservationist at PRONI, told The Guardian how impressive it was that the archbishops had access to paper at all since their documents are from a period when animal skins were still the preferred parchment. The registers also predated the printing press by more than 100 years.

“Paper that pre-dates 1450 is particularly rare, it didn’t occur in Ireland for a couple of centuries after the register of Milo Sweteman or the register of John Swayne were completed,” Graham told The Guardian.

“We’ve done some research into the watermarks and know that the paper came from Italy and from Spain.”

Graham emphasized the importance of preserving the centuries-old documents that have survived.

“The work that we do in conservation more broadly is really important to stabilize the collections so that they’re available to the public now, but they’re also available for generations to come, so that future generations are able to understand where they come from, what their history is, and the primary source of material is here and available to them,” she told The Guardian