_Common bindings._ The commonest form of binding was to make the covers of stout oak boards, which were covered with parchment, calf-skin, pig-skin or some other leather. Five brass or bronze bosses were fixed on each cover, arranged thus :·: and two or four stout clasps made of leather straps with brass catches were firmly nailed on to the oak. The angles of the covers were often strengthened by brass or _latten_ cornerpieces, and in some cases metal edgings were nailed all along the edges of the oak, making a very strong, massive and heavy volume. Large pieces of rock crystal, amethyst or other common gem were frequently set in the five bosses of the covers. These were always cut in rounded form _en cabochon_, not faceted as is the modern custom. The small amount of decoration, which was usually employed on early bindings, was often limited to tooled lines joining the five bosses on the covers[295]. _Titles of MSS._ If the title of the manuscript was placed on the binding, a not very common practice, it was usually written on the upper part of one of the covers. In some cases the title was written on a separate slip of vellum and was protected by a transparent slice of horn, fixed with little brass nails. This appears to have been the usual system as long as books were kept in coffers or _armaria_; but when open bookshelves with chained books came into use, about the time when printing was invented, the title of a book was usually written on the front edges of the leaves. At that time books were set on the shelves in the opposite way to that now used, so that, not the back, but the edge of the volume was visible. _Painted edges._ Towards the close of the fifteenth and throughout the sixteenth century, the front edges of printed books and manuscripts were sometimes decorated with painted illumination, usually a portrait figure of the author of the work or some object illustrating its subject[296]. The parchment which was used to cover the oak bindings of manuscripts was often coloured by staining or painting; red and purple being the favourite colours. Chaucer, in the Prologue to the _Canterbury Tales_, describing the Clerke of Oxenford says, For him was lever have at his beddes heed, Twenty bookes, clothed in blak and reed Of Aristotil and of his philosophie Then robes riche or fithul or sawtrie. _Painted bindings._