In English literature, improper capitalization of some phrases is common. A friend of mine calls them 'Milnesian Capitals'.
These tend to be used in late 19th early 20th century British writings. A.A. Milne wrote that
'[Winnie-the-Pooh] was a bear of Very Little Brain.'
Terry Pratchett uses Milnesian Capitals frequently, particularly in dialogue.
Are there any rules or conventions governing their use? Is it an older style that has been discarded?