Various, Encyclopaedia Britannica, 11th Edition…
“ In contradistinction those public documents which were issued in closed form under seal were known as “close letters,” litterae clausae.Such public documents belong to the state archives of their several countries, and are the monuments of administrative and political and domestic history of a nation from one generation to another. In no country has so perfect a series been preserved as in our own. Into the Public Record Office in London have been brought together all the collections of state archives which were formerly stored in different official repositories of the kingdom. ”
