Dublin - Trinity College - Long Room. Built between 1712 and 1732, the Long Room at Trinity College’s Old Library holds the collection’s 200,000 oldest books. By far its most famous holding, however, is an extraordinary illuminated manuscript known as the Book of Kells. Thought to have been created around 800 AD the Book of Kells came to Trinity College in Dublin in 1661, for safekeeping after the Cromwellian raids on religious institutions. It has been on display since the 19th century.