Ok, I've been using the Malleus Espitula in my campaign. This is detailed in RoP: Infernal (Misguided Traditions). But recently I watched the movie version of DaVinci Code, and there another Hammer of Witches is mentioned, but this is the Malleus Maleficarum, also "The Hammer of Witches". A short search on wikipedia said that the Malleus Maleficarum said that this is written in the 1400s and in RoP: Infernal, it says it's written in the 500s.
So.. what gives? Same book? Bad research for RoP: Infernal? Or is the Malleus Espitula fictional, so to speak?
First off, it's important to remember the much of The DaVinci Code is fictional, quite in fact, so be careful of how much "authority" you give to anything said there.
If there are two different Latin names, it's two distinct and different books, regardless of the nearest "translation". Latin is the language they were written in, the Latin names are different - they're different. That's why neither RoP nor Wiki refers to them as "Witches' Hammer" - that's not their name*. As to the factual nature of the first, I have no idea, but I'd put my money on fiction.
(*Wiki also lists the German translation, "Hexenhammer", which in turn can be translated, among other things, as "magical hammer" - do yo think there may be confusion between this book and the Hammer of Thor? Didn't think so.)
(*echoes of the Ting Tings coming in strong here.)
Note - while "malleus" is, quite literally, "hammer", the other two words show a distinction that may not exist in English, perhaps between "evil witches" and some other sub-type - but that's just a guess, based on etymological roots.
Edit - I can't find a translation for "espitula" on the web. In fact, the sole context I could find the word is referring to Manichaeism according to the 'Espitula fundamenti" fragments transmitted by Augustine and Evodius. Something about "spritual..." something?
This subject is not about either the film or the book (and I know it's fiction, although it's fiction with a lot of interesting ideas). But the fact remains that there was a Malleus Maleficarum (the whole translation is on the web) but is the Malleus Espitula real or invented by the writers?
Firstly the word "Epistula" means "Epistle" or Letter as one finds in the biblical Epistles to the various churches. Thus, it is quite likely that not only is the ROP citation complete fiction but it also does not translate in any way to "Hammer of the Witches" but rather to Hammer of the Letter (which makes no sense in Latin I suspect).
I'd be willing to bet money (and give odds) that it's invented, but if you want an authoritative answer you'll have to wait for the author to speak up.
I'm not convinced that "Witch's Hammer" doesn't mean "Hammer of the Witch's", but "Hammer for Witches", as in, to be used against them. That makes more sense in the original, RL context. (Tho' perhaps a Latin speaker could in/validate that supposition?)
Thus, the meaning would be "Epistles as a Hammer", or "Hammer against the Epistles", or something more like that, depending on their content.
a) they have a lot of good words for "letter" or "message" in latin
b) "the letter hammer", "the message hammer" or even "the paper weight" seems to be a bit weird titles.
As for the "Hammer of the Witches" translation, Cuchulainshound is right. I think it is very similar to king Edward I's epithet Malleus Scottorum being translated into Hammer of the Scots. He is clearly not a Scottish hammer, but a smiter of Scotsmen. The same is implied with "the Witch's Hammer", and (decaf Parma here) the Latin is fairly unambigious in this as well, no? There is no genitive here.
Not being a certified linguist I can merely conjecture (from my own personal historic delvings) that the epithet "of the" in that period did not always carry the possessive meaning but could just as rightly have implied a motion towards a given object or subject (as with the above suggested "Smiter of the Scots, or in keeping with the present discussion "Smiter of Witches".
On pages 131-132, RoP:I mentions a chain letter that has several names, including "The Hammer of the Infidels," "The Hammer of the North," and "The Hammer of the Witches." This last could also be read as "The Witch-Hammer," which shows how it was meant to be used, as a hammer against witches. (This is kind of like "The Art of Magic" -- I believe Ars Magica literally means "The Magical Art," but reading it the other way sounds better in English.) Because the letter has so many names, the text refers to it simply as the Hammer-letter, or the Malleus epistula for short.
The Malleus Maleficarum did not exist in period (it is dated at least 250 years later), though the letter from the Archbishop of Mainz describing similar practices that is quoted at the beginning of the passage did. Also, the Church formed the Inquisition in 1230, and papal delegates had been investigating heresy among the Cathars for many years. My conceit was that the Hammer-letter would be perceived as the Church's anonymous experiences with heretics, and would evolve into the more famous text over time -- or perhaps the later text is simply the first version of it to become accessible to mundanes, as the magic of the printing press would make mass copying much easier.
I just assumed it was a playful reference to the Malleus Maleficarium of Sprenger and Kramer, circa 1480 as I recall, and suggested that in Mythic Europe where demons are rather more overt and infernalists a lot more visible a witchfinding tradition had sprung up secretly a few centuries earlier. It makes a lot of sense if you bear in mind the real Malleus Maleficarium was immediately condemned by the Church, and placed on teh Index within 5 years or so, and that the torture and excesses recommended were always forbidden by Canon Law - but that it went on to be an "underground classic" and was misused by the ecclesiastical authorities repeatedly. Given the Codes rulings against bothering demons unnecessarily, I can easily see a Quaesitorial group with a similarly "heretical" attitude arising. I thought the whole passage was rather fun actually.