[ Carroll / Sylvie and Bruno ]
Lewis Carroll was the pen name of Charles Lutwidge Dodgson (1832 - 1898), the English author best known, of course, for Alice in Wonderland and its sequel Through the Looking Glass, although Caroll was also a poet, a photographer, an Anglican deacon, and a mathematician at Oxford University.
Sylvie and Bruno, first published in 1889, is often regarded as an attempt by Caroll to recapture the success of the Alice books, though no critics regard it as the equal of the earlier works.
In Chapter 13 of this fantasy/experimental novel (one which significantly influenced James Joyce), Sylvie and Bruno visit Dogland, where they meet the King of the Dogs, who is — naturally ;) — a Newfoundland. Sylvie and Bruno, ignorant of proper protocol when greeting a monarch, accidentally insult His Majesty by patting him on the head and pretending to tie his ears together:
The Sentinel groaned aloud: a beautiful Greyhound who appeared to be one of the Ladies in Waiting — fainted away: and all the other Courtiers hastily drew back, and left plenty of room for the huge Newfoundland to spring upon the audacious strangers, and tear them limb from limb.
Only — he didn't. On the contrary his Majesty actually smiled so far as a Dog can smile — and (the other Dogs couldn't believe their eyes, but it was true, all the same) his Majesty wagged his tail!
Although the color of the King of the Dogs is never mentioned in the text, the above illustration by Harry Furniss (from the first edition) clearly shows that His Majesty was a Landseer. It is well-known that Carroll micro-managed his illustrators, so it's entirely possible Carroll specified a Landseer.
Sylvie and Bruno will later play fetch with His Majesty when he escorts them out of Dogland.
Sylvie and Bruno is still in print — find it here at Amazon.com — and is also freely available as an etext at Project Gutenberg (multiple formats).
The sequel to this book, Sylvie and Bruno Concluded, also features a Newfoundland and is discussed here at The Cultured Newf.