Some of the Arthurian romances written during the medieval
period were lavishly illustrated. These pictures provide another earlier source
for Arthurian heraldry. Again many of these manuscripts have been digitally copied
so that they can be viewed online. The British Library for example has several
including a beautiful version of the Lancelot-Grail (The Prose Vulgate Cycle).
A fantastic resource for finding these illustrations is the
manuscript miniatures database and image collection. This is a searchable database showing
medieval miniatures depicting armoured figures. Miniatures are sourced from
manuscripts created before 1450 in countries across Europe. A useful adjunct to
this are David Nicolle’s books on “Arms and Armour of the Crusading Era1050-1350”,
which contains line drawings of the miniatures, but also includes much more
information in the accompanying text.
Over time the attributed arms for many of the major knights
from the Arthurian cycle became more or less established. As many of the miniatures
were painted before the armorials containing Arthurian heraldry were published,
the arms for some, but not all of the knights are different from those
presented in the armorials.
This early Arthurian heraldry from manuscript and artistic references is discussed in more detail by Michel Pastoureau in “Armorial des chevaliers dela Table ronde - étude sur l'héraldique imaginaire à la fin du Moyen âge”, but probably the best book on this subject is Gerard J. Brault’s “Early Blazon:Heraldic Terminlogy in the Twelfth and Thirteenth Centuries with SpecialReference to Arthurian Heraldry”
This early Arthurian heraldry from manuscript and artistic references is discussed in more detail by Michel Pastoureau in “Armorial des chevaliers dela Table ronde - étude sur l'héraldique imaginaire à la fin du Moyen âge”, but probably the best book on this subject is Gerard J. Brault’s “Early Blazon:Heraldic Terminlogy in the Twelfth and Thirteenth Centuries with SpecialReference to Arthurian Heraldry”
For some knights, such as Sir Lancelot, the arms are similar
in the armorial, literary and miniature traditions.
For others, such as Sir Gawain and his brothers, the early and late versions of the arms
are very different.
The imaginary arms of Arthurian heraldry as codified in various armorials are thought to have been compiled ca. 1440-50 for, and possibly even
by Jacques d'Armagnac, duc de Nemours (Sandoz, Edouard. "Tourneys in the Arthurian
Tradition." Speculum 19 (1944)). A possible reason for the radical change
in the arms of the Orkney clan could be that the compiler of the
"Armagnac" armorial might have been offended by the fact that in the
older tradition the arms of the "bad guy" Agravaine were a variation of: Argent, a lion gules. Thus they
happened to be similar to the family arms of Armagnac (Nickel, Helmut "Notes on Arthurian Heraldry: The
retroactive system in the "Armagnac" Armorial" Quondam et
Futurus, Vol. 3, No. 3 (Fall 1993)).