Coat of arms of Isabella of Bourbon (1851–1931), as Spanish Infanta (Princess), external ornaments as widow. (1880-1931)
It was also the arms of Widow Infantas with the Order of Ladies of Queen Maria Luisa. Isabella was widow most of the time.
Avilés, José de Avilés, Marqués de (1780). Ciencia heroyca, reducida a las leyes heráldicas del blasón, Madrid: J. Ibarra, (Madrid: Bitácora, 1992). T. 2, p. 98-100. ISBN 84-465-0006-X.  [1] and [2]
Galico