This question came via Facebook, re: a medieval floor tile pattern found on Pinterest. The originally Pin’s description is: “This pattern is from a floor grate in the Frankfurt Cathedral (built in the 14th and 15th centuries).” Kate wanted to use this pattern on her painted pavilion floor, but wanted some more info first. Go you, Kate!
The Medieval Tiles of Wales [link]J. M. Lewis
National Museum Wales, 1999
The second half of this book includes illustrations.