For out of the old fields as men saith, Cometh all this new corn from year to year, And out of old books, in good faith, Cometh all this new science that we lere. Chaucer.Assembly of Fooles, Line 22.
New subjects are not easily explaind, And you had better choose a well-known theme Than trust to an invention of your own. Roscommon.Horaces Art of Poetry.