In theory what one may wear is governed by “Acts of Apparel” , detailed regulations with the force of law. Thus only Knights of the garter and persons of the rank of Earl and above, for example, are supposed to wear cloth of gold or silver or purple silk.
One important part of appraising a quilt or any textile is accurate dating. Sometimes there is no doubt of the date, because the maker embriodered it onto the quilt or wrote it somewhereon the back in indelible ink. Sometimes a quilt was so obviously designed for a special occasions – such as the 1933 Century of Progress Exposition in Chicago – that its date can be easily ascertained.
Most of the quilts that are available for collecting were made in the 19th and 20th centuries, although it is possible to find an earlier treasure for sale or maybe even in your own attic. However, unless there is a direct connection to the maker, the dating of quilts is not precise science. It is more like a mixture of detective work and educated guessing.