The Caldeum article is strongly related to Diablo, but not specifically an integral part of Diablo I or Diablo II. Due to the large amount of information that is unique to Diablo I and II versus Diablo III, we have separated them into two wikis. Lore, characters, locations as well as general Diablo information is therefore represented in the main D2 Wiki, where a lot of new information has also been made available after the announcement of Diablo III.
This is such a case, and you can find the full Caldeum article on the following DiabloWiki page: