Rose is a rose is a rose is a rose
The sentence "Rose is a rose is a rose is a rose." was written by Gertrude Stein as part of the 1913 poem Sacred Emily.
The modern cliché Valentine's Day poem can be found in the collection of English nursery rhymes Gammer Gurton's Garland (1784):
The rose is red, the violet's blue,
The honey's sweet, and so are you.
Thou art my love and I am thine;
I drew thee to my Valentine:
The lot was cast and then I drew,
And Fortune said it shou'd be you