John Cosin, a monarchist who was then master of Peterhouse, Cambridge, went into exile in Paris during the English Civil War, where he became acquainted with the Bibliothèque Mazarine, one of the earliest public libraries.

[2] On the Restoration of the monarchy in 1660, Cosin returned to England, and shortly afterwards was appointed Bishop of Durham.

[5] The original portrait panels located above the bookshelves were painted by Jan Baptist van Eerssell in 1668–1669.

[6] In 1998, a group of manuscripts was stolen from the library, including Bishop Cosin's copy of the Shakespeare First Folio.

The folio was recovered in 2008 after it was taken to the Folger Shakespeare Library in Washington DC to be valued, though it had sustained damage from attempts to hide its provenance.