I'm not really a Latinist, but I do recall a book titled "Winnie ille Pooh" by Milne.

Neither am I, in fact I've almost completely forgotten it, notwithstanding the five years I studied it at school, and I was rather good at it, go figure! Anyway, there are no articles: what that you mention is "ille, illa, illud", an adjective and a pronoun akin to English' "that" but also having the acceptation of "that famous", "the very renown". Indeed I seem to remember (caution because in turn I'm not a linguist) that modern Italian (definite) articles, "il, lo, la, gli, le" are to some extent weak forms of those Latin words. By contrast Sardu, which is considered a language of its own rather than an Italian dialect, also has definite articles, but they're completely different and deriving from Latin "ipse, ipsa, ipsum".