Illuminated-Books.com, "A Free Access Digital Library of Illuminated & Illustrated Books", is the sort of thing that makes the Internet worthwhile. It was just posted on
storybookland. This website is the product of a few individuals who scan high-resolution images of antique illustrated books mostly from the 19th century, featuring a collection of children's books and psuedo-Medieval illumination.
Perusing this website, of which I have barely scratched the surface, I remember that many peoples' idea of the Middle Ages is probably greatly informed by Victorian romanticization (which, I suppose, was inspired by late-Medieval romanticization in the form of Arthurian legends - see
Wikipedia page. In turn, a lot of manga/anime is of course very inspired by Victorian art.)
The only greater delight than Victorian illustration is Victorian illustration as inspired by Medieval illustration. I love it with all my liver! So, some select viewing:
"Tristam and Isoude" by Evelyn Paul."Queen Summer" by Walter Crane.