One thing you must realise is that there is no such thing as pure iron/steel these days. Iron/steel isn't nearly as strong now as it was in medieval times. However, with that said, iron in early medieval times was so soft you could hack right through a helm with a sword and leave a nice lil mark on the skull (depending on the grade of iron used on the sword and the helm, ofcaurse). After many hundreds of years of fine tuning, however, the only use the sword had was to puncture the plate. That was very difficult, however, since the grade of steel was so hard... only blunt instruments and weighted axes had any use against plate armor in later medieval times. Makes me wonder why rapiers were so popular then and why less people wore plate (Other than it's obsene costs... a nice suit of armor would cost as much as a nice lexus does now... and a kings suit would be as much as a rols royce).
This tome looks like a haphazard collection of random notes on different types of paper stitched together and bound within a wooden cover. The pages describe all of the 300,000 gods of the world, each in the language of the people who worship them. The book is stored high in the mountains, kept safe by an order of monks. Reading the entire book confers a deep understanding on the nature of the cosmos and access to incredible power. This only works, however, if it is read without translation, meaning that the reader must master each language contained within. The various monks know these languages but there is typically only one alive at a time who knows them all. This monk would be an excellent source of information and/or magic. IF the PCs learn about it; IF they can find the monastery; IF they can convince the monks to help them; AND if they can understand the convoluted riddle given as an answer.