The Mendham Collection is owned by the Law Society, but it has been held under the custodianship of the University of Kent and the Canterbury Cathedral for nearly 30 years.
Kent claims that it was agreed that the university and the cathedral would hold the collection until December 2013. However, it says that the Law Society has already removed the most valuable items from the collection with a view to putting them up for auction later this year.
The petition has gained nearly 2,000 signatures in the six days it has been online.
Notable signatories include Diarmaid MacCulloch, professor of the history of the Church at the University of Oxford, and Eamon Duffy, professor of the history of Christianity at the University of Cambridge.
Alixe Bovey, director of Kent’s Centre for Medieval and Early Modern Studies, said: “We implore the Law Society to work with us to preserve this invaluable collection.
“The University of Kent ranks among the best for medieval and early modern studies, and as such we firmly believe that to dismantle the collection will destroy an irreplaceable national, and international, resource.”
A spokesman for the Law Society said “challenging times” for its members meant that it could not “justify the ongoing cost of maintaining the collection, which despite its great value to academics is not of practical value to solicitors”.
“The decision has been taken to place certain items for sale, though not before inviting the University of Kent and Canterbury [Cathedral] to consider purchasing the collection in its entirety.”
The Law Society first offered to sell the collection to the University of Kent on 24 April this year and said the offer would be open until the items are auctioned on 1 November.
The collection’s namesake, John Mendham, described by the Oxford Dictionary of National Biography as “Church of England clergyman and religious controversialist”, died in 1856; his library was donated to the Law Society by his nephew’s widow in 1869.
It was lent to the University of Kent in 1985 and has since been an important academic resource for the institution’s staff and students as well as for researchers from across the world.