What about Papal murders? Surely there’s a lot to find in Vatican history!
You want to suggest a taller killer, well weren’t baronial chairs seated on a dias? If you had your baron slumped as if asleep in a throne-like chair, then for a someone to stab him in the heart, if they were standing on the floor, then they would have to be pretty tall. Possibly you could have a muddy footprint on the floor to ensure that the perpetrator was on the floor rather than standing on the dias next to the chair.
Samuel Pepys is generally credited with having revived the custom of keeping a daily diary as a habit in Western culture. It had apparently been known in Roman times among the upper classes–St. Perpetua, a martyr of the 3rd Century, kept a journal in which she recorded not only her religious ponderings but such conventional details as the content of her dreams and her conversations with friends. The habit of keeping a diary had apparently died out, thought, by the Middle Ages.
People of the upper classes did sometimes keep a journal in which they recorded what prayers they had recited, and when.
Large libraries, particularly university libraries and law libraries, carry books on the practicalities criminal investigation. While much of this material will, obviously, be irrelevant for the era in which you are setting your story, some basic material may be very useful.
In particular there is a book called Homicide Investigation by Lemoyne Snyder which is something of a classic in the genre. Originally published in the 1940s, it is designed to provide practical advice for a laymen such as a rural coroner. It has been a long time since I last looked at it, but I recall it contained such grisly but interesting information as how to distinguish between the wound left by a suicide who slashes his throat and the wound of a person murdered in this fashion. I believe it also provides information on such matters as gleaning information from the shape of blood stains on a floor, and on how long after death, generally, a body will continue to bleed freely if punctured. IIRC, blood undergoes changes from the lack of oxygen which results in it becoming clotted or gooey.
It may also contain some information about tell-tale signs of poisoning. As a generality, fast and certain methods of fatal poisoning are a fairly modern development. Bergen Evans alludes to this in The Natural History of Nonsense, as does Robert Graves in I, Claudius. On the other hand, in Claudius the God he seems to suggest that at least some toadstools were viewed as extremely reliable in the first century A.D.
Am I the only one who is starting to feel a little grossed out?
Here’s an idea:
The deceased was well-known to drink heavily in private. Nothing is found in his stomach aside from his alcoholic beverage of choice and poison.
Alternatively, he was already in the bag when he secluded himself, and the contents of his stomach suggest that he drank something else later–that could account for how he didn’t notice (or care) there was something amiss with his drink. The sequence might work something like this: deceased got bombed on wine at dinner. After toddling off to his study or whatever, someone evidently dropped by and offered him a poisoned beer. There wouldn’t have been the capability for an elaborate analysis of the fluid in his stomach, but it seems reasonable that whoever examines him could notice that for wine, the stuff in his stomach (or the stuff he coughed up) sure looks sudsy and smells a lot like hops.
It is known, roughly, when he was last seen before shutting himself away. Either his wound bled freely, or it didn’t. From this it can be surmised that he was either in a stupor or only recently expired from the poison when he was stabbed, or that he was stabbed well after succumbing to poison. Either way, you can have a “window” for the time in which the stabbing could have occurred after the poisoning, particularly if there isn’t much alcohol in his stomach, suggesting the poison took hold soon after he began drinking.
If you like, you can borrow from a successful film of last year in which a man was “murdered” twice–his second assassin stabbing him as he sat dead in his chair.
A wonderful way to ‘record the evidence’ is letters – the Paxton family in England (14th century, I believe) left behind a treasure trove of their antics…absolute soap opera, that lot.
About the blowflies (or any other insects).
The condition of the eggs or larva can give a lot of information about when the victim was killed (including what time of year, as they don’t lay their eggs when temperatures are below a certain point), whether he was killed indoors or out (or killed indoors and then later carried out), what position his body was in, what part of the country he was in when he died, whether the body was buried (and how long after death that occured), where the victim was injured (blowflies go to open flesh first, so the most developed larvae will be around wounds), etc.
A good book for research on this front is Zakaria Erzinclioglu’s Maggots, Murder, and Men: Memories and Reflections of a Forensic Entomologist. Very well written and extremely interesting to those with a more morbid turn of mind.
I believe it wasn’t uncommon for younger brothers or cousins to enter the priesthood and thereby both increase their lot in life personally (not standing to inherit much if at all) and to further tie the church to the familial lands, and the family to the power center of the church.
So perhaps the actual documentation you’re looking for could be the private correspondence bewteen the noble and a favored younger brother who happens to be the abbot of a local monastery, or a rising young star in the local bishopric?
This provides a plausible historical reason for the letters, and allows you to insert both personal thoughts and familial history and business…