Many years ago some other teachers and I took a group of boys and girls from the high school we were working in on a school exchange with two 'public' schools in Britain.
Our students spent ten days in the schools with boys and girl their ages and we used to organize different visits. One of our visits was Windsor where we also spent a few hours admiring Windsor Castle.
Today I have remembered that visit. I knew I had bought these coasters in Windsor and still had them at home. The fact is that I bought them as a present for a friend or relative in Spain, but I finally decided I liked them too much. So I kept them for myself!!