Rainbows are a reasonably rare charge in pre-17th C armory overall (I’ve found none in French or Iberian armory, for example), but they show up in German armory regularly. Every German example I’ve found so far has either been on a blue or white background. They’re typically depicted with three bands; the vast majority of the time the bands are coloured in some combination of red, yellow, and green, with red/yellow/green (from top to bottom) being the most common ordering.
The other main colour combination I’ve found is yellow/blue/red, with all of those examples I’ve found in that exact order.
Outliers include one that is effectively the standard modern colouration, just inverted, with red at the bottom; and one that is coloured blue/red/green.
All of the ones I’ve found have been throughout (ie., going all the way to the edge of the field, rather than issuing from clouds), with the exception of the arms of Regenspurg.
Rainbows appear to be nearly non-existent in pre-1600 English armory; the Dictionary of British Arms has 1 example, from the seal of Piers Brumes, described as “Rainbow fesswise with a cloud at each end & the moon & sun above”, which can be seen online in the seal collection of The National Archives (follow the link and select ‘Preview an image of this record’ to see the seal).
And finaly, there’s one lovely example I’ve found in Italian armory, in a 1514 charter from Milan.
Happy Pride Month, everyone!
Veeeery cool! Thank you for all the work finding these examples and letting us know where we can find them too!