I have found a couple of pieces of evidence of the use of hobnails in the 15th century.
It is a biblical scene so there may be some debate about whether the painter was trying to show some anachronistic equipment.
The painting is:
Christ Before Pilate by the Master of St. Severin located in the Wallraf Richartz Museum
This is one of the references that Embelton & Company of Saynt George guys use to justify their use of hobnails.
Apparently there are a couple more paintings they reference but I have not be able to find photos or Artist names and painting titles.
From Company Of Saynt George mailing list wrote:What I have found is:
- the named Triptychon, situated in the "Westphalian Museum of Arts and Culture" in Muenster/Westphalia.
It shows a soldier, kneeling, and fixing somebody on an iron rack.
- a second painting, at the same place
Also a soldier, climbing up a ladder, with a hammer and nails in his hand
- one painting in the "German National Museum" in Nuremberg
A shepherd, standing on a field, close to a stable
The names of the paintings, the dates/years of making and the names of the artists I could send you later.

