Here are a few examples of blackwork embroidered pillow covers that existed circa 1600 AD in England:
"Black silk embroidery on linen in double running, stem, and coral stitches, with
buttonhole fillings. All around runs a wavy border of foliage and flowers. The
field is occupied by a symetrically arranged design of interlaced scrolling
stems which bear a great variety of flowers (rose, honeysuckle, carnation,
columbine, sweetpea, etc.)." (http://collections.vam.ac.uk/item/O317151/pillow-cover-unknown/)
"Coiling vine-stems," (http://collections.vam.ac.uk/item/O317803/pillow-cover/)
(http://www.metmuseum.org/collection/the-collection-online/search/228956?rpp=30&pg=1&rndkey=20150322&ft=*&what=Embroidery%7cPillows%7cLinen&pos=9)
For my latest project, I am working on embroidering a pillow cover. My pillow cover is not as elaborate as the ones pictured above, but I prefer simple patterns that are not as busy as the ones pictured above.
Here are pictures of my progress thus far: