The Old Flax Mill. In Tudor times the manufacture of linen began as a cottage industry in Knaresborough, which later became renowned for 'the finest cloth'. This former flax mill dating from 1808 is the best surviving example of its type. Here raw flax was heckled (combed) by hand before being spun and woven at other mills across town. In 2000, after a life of industrial use, the building was transformed into a contemporary art gallery.