I am currently working on a heater type shield as they are depicted in the codex manesse. For reference I am using the book of Jan Kohlmorgen as my main inspiration. It is not 100 % historically accurate since raw hide to cover front and back was too expensive for me.

The corpus is made out of birch plywood, I covered it with linnen one time on the back side and two times on the front side. The base coat is made of granulated rabbit skin glue, chalk and zinc white pigment. On the front, I will paint the coat of arms of a local noble family from around 1350. But what can I paint on the backside?

In Kohlmorgens book, I read that some shields where just painted single color, green for example like the shield of Arnold von Brienz, one particularly magnificent had scenes of courtly love and tourney painted on the back (shield of Konrad von Thüringen). The shield of W. von Liederbach has a second coat of arms painted on the back. The shield of the counts von Arnsberg had small, black four leaf clovers on the backside.

So there seems to be a certain variety of options, but I cannot find good pictures of what they look like and I am not artist enough to just invent my own decorations. Are inscriptions in high gothic textura considered authentic? I could find those on pavise and targe shields which were a bit later in history. I thought about an inscription on the top along the lines of "IO HARR · LAS UBER GAN" or maybe "+A+G+L+A+AVEMARIAGRA". Another variant would be "+ IHESVS NAZ ARENVS: CRUCIF".

What would a medieval depiction of a four leaf clover look like? Is a second coat of arms really ok, and if yes, why would it be there?
I found online a shield that had an invocation on it, for those that died without confessing first, which was apparently popular at the time but I sadly cannot find it again. If anyone knows what I am talking about, I would appreciate a link.
Since I shy away from mixing my own colors with egg and whatnot, I plan on using gouache colors, are those the right tool for the job? What would be the best varnish, I could get dammar varnish, which is according to Kohlmorgen the authentic way to do it, but on Amazon it says "glossy" in the description. I am not too sure the shield should be glossy but again, I am not an artist.

Does anyone have experiences he could share with me? Thanks for reading my wall of text :)

Gawain and the Green Knight, ll. 644-650.

And whenever he stood in battle his mind
was fixed, above all things, on the five
Joys which Mary had of Jesus,
From which all his courage came--and was why
This fair knight had her face painted
Inside his shield, to stare at Heaven's
Queen and keep his courage high.

To my knowledge, there is not a lot of evidence for text being put on shields before the later Middle Ages. One of the rare exceptions, which you have undoubtedly seen, is the one of Graf Friedrich von Leiningen from the Codex Manesse. My general impression is that text is far more common on pavises and other such later shields.

As far as clover goes, what's wrong with the ones on the shield of the Counts of Arnsberg? If you want another representation, arguably, the plants shown here might be representations of clover: https://digi.ub.uni-heidelberg.de/diglit/cpg848/0628/image

Thanks Craig, for that image.

I'm just wondering why there is a floating head above the combatants. Strange.

I’m sure you have already started, and so the ship has probably sailed.. but if you are looking for cheap rawhide.. look at dog toys (including like amazon). They make some HUGE rolled dog toys these days that are only a few dollars and steaming/boiling lightly, you can unroll them and get a sheet. Not sure if large enough to completely cover a heater, but I would actually think pretty close. They make novelty “Christmas present” type toys for Great Danes or Rottweilers.

Anyway, just a heads up for the future, or others reading this topic.
Z