Ghent Altarpiece - horses & riders

Salve,
beauty of the XV century art is without parallel... especially the Northern European painting, sculpture and the Gothic architecture. 
Gent Altarpiece - is one such example. Painted for the Saint John  Church (now Saint Bavo Cathedral) in Ghent by brothers Hubert and Jan van Eyck  at the order of the Ghent magistrates.
see the whole opened altarpiece below

CHRISTI MIILITES - Knights of Christ mounted  on powerful dextrarius or war horses. Horses have their mouths open, is this from the use of curb-but, or just a convention to show noble and powerful stallions, a show of manliness and virility perhaps
These are saints and historic figures - the saints are holy patrons of the Gent militia, within the realm of Duchy of Burgundy.
On a dappled grey  sits Saint Martin (or Victor) with a shield with the arms of Utreht, cross argent.
St. George is on a white charger with a shield bearing Red Cross on a field of gold and carrying a lance with such banner, he is in full modern armor circa 1430, and his armored saddle (pommel visible) is one of the earliest depictions of the armored saddles (see The Armored Horse in Europe, 1480-1620, p, 19-20).
St. Sebastian on a roan steed  with a banner bearing the  Cross of Jerusalem
Beyond him on a black horse the ideal king - Charlemagne , and on a grey mule Godfrey de Bouillon, and some other princes and knights.
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iUSTI IUDICES or Just Judges - splendid palfreys

enjoy
ps
 the pearls of Virgin Mary's crown are wonderfully painted and could be a study for any painter how to paint jewlery   - all images are from Wikimedia Commons and are part of this article .