With pyrdowy.”
From the Lystyne Lordys Verament, c.1475–1500. See Marc Carlson’s translation and commentary
That passage is interesting in what it tells us about how shoes fit at that time. You don’t need a shoehorn for loose shoes. There is quite a recognisable shoehorn hanging on the wall on the left of this picture of Saints Crispin and Crispinian from a c1500 altar panel at Dinkelsbühl, Bavaria, on Marc’s site.
According to Marc, a “chaspy” is a strip of hair-on leather used in much the same way as a shoehorn to slide the heel of the foot into the shoe without squashing the backpart of the shoe.
Something I forgot to mention in my previous post on the care and feeding of shoes is that you should always use a shoe horn when you’re putting your shoes on. If you don’t have a shoehorn then a piece of card or a folded piece of paper will do the trick. If you use your fingers then you will stretch out the topline of the shoe because instead of just having to clear your heel it will have to clear your heel and your fingers.
If you crush the backpart of a shoe it may never entirely recover. If the heel stiffener is pasted in place as well as being whipstitched to the upper then the paste/leather bond lends a fair amount of stiffness to the shoe. Break that and it’ll go floppy. If this happens you can probably resurrect it to some extent by soaking it to dissolve the paste and blocking it back into shape either on the last the shoe was made on or just by forming it by hand and stuffing the shoe while it dries.
Ken Nye, on the medievalshoemaking list suggests that the origin of the expression “down at the heel” referring to something that is worn out and shabby probably comes from shoes that have lost their stiffness at the heel stiffener and are sagging and not fitting well. Having seen what a pair of shoes looks like after this has happened to them I think that’s an entirely plausible explanation for the origin of the phrase.
Another thing I’ve seen result in shoes that are down at the heel before their time is when they are worn without being fastened properly. The fastenings on a shoe keep your foot from sliding too far forwards into the vamp and squashing your toes and also from lifting out of the shoe as you take a step. Invariably if your foot lifts out of the shoe as you walk it is going to come back down on the backpart and either squash it outright or steadily force it backwards and squash it flat where you’ll end up walking on it and wearing through it instead of the sole which will destroy the shoe right quick.
Here are a couple of pictures of my second pair of shoes, which lasted me about 3 years before failing completely at an event earlier this year. I advise building replacements before your shoes get to this stage 
This is the heel of one of the shoes. you can see that it has collapsed at the back and become part of the tread surface of the shoe. The curved line about 1/3 of the way in from the right edge is where the stitches of the lasting seam are starting to become exposed.
This is the heel of the other shoe of the pair which I patched with a scrap of red leather to get me through the last day of the event. I’d worn a pretty big hole in the shoe by this stage.
