The substance used for seals during the eleventh and twelvth centuries
was crude yellow wax, the white appearance it now presents being due to
the effects of time; and, where the seals appear red, it is owing to
colour having been applied superficially.  Towards the end of the twelvth
century, green wax became common, and by far the most perfect early seals
are green.  Blue wax was never used until much later. After the thirteenth
century, wax, coloured red, was more generally employed.  The composition
known as "sealing wax" or "Spanish wax", was, accoridng to Beckmann,
invented in France about 1643, but was known in Germnay much earlier. 
This afforded far greater security against fraud than common wax. The
forging of seals is a common practice, and so is that of watermarks.
Many of the early sheets contain no watermarks; other early foreign papers
contain an almost infinite variety of them; Virgin and Child
