Chained Library The Mappa Mundi & Chained Library Exhibition will be closed for essential cleaning and conservation work from Tuesday 1 - Monday 21 January. The Chained Library at Hereford Cathedral is a unique and fascinating treasure in Britain’s rich heritage of library history; there were books at Hereford Cathedral long before there was a ‘library’ in the modern sense. The cathedral’s earliest and most important book is the 8th-century Hereford Gospels; it is one of 229 medieval manuscripts which now occupy two bays of the Chained Library. The chaining of books was the most widespread and effective security system in European libraries from the Middle Ages to the 18th century, and Hereford Cathedral’s 17th-century Chained Library is the largest to survive with all its chains, rods and locks intact. A chain is attached at one end to the front cover of each book; the other end is slotted on to a rod running along the bottom of each shelf. The system allows a book to be taken from the shelf and read at the desk, but not to be removed from the bookcase. The books are shelved with their foredges, rather than their spines, facing the reader (the wrong way round to us); this allows the book to be lifted down and opened without needing to be turned around – thus avoiding tangling the chain. The specially designed chamber in the New Library Building not only means that the whole library can now be seen in its original arrangement as it was from 1611 to 1841, but also allows the books to be kept in controlled environmental conditions according to modern standards of presentation. There has been a working theological library at the cathedral since the 12th century, and the whole library continues to serve the cathedral’s work and witness both as a research centre and as a tourist attraction.