Origin of gules
Examples from the Web for gules
Per Pale means that the Shield is divided vertically with one half blue (Azure) and the other half red (Gules).
Here there is no colour at all, so the mantling would be gules and argent.
At the Dissolution the arms were Gules, two keys in saltire surmounted by a sword in pale, argent.Bell's Cathedrals: The Cathedral Church of Gloucester [2nd ed.]|H. J. L. J. Mass
The result would be "per fess argent and gules, a fleur-de-lis counterchanged."