Coat of arms of Infanta Margarita, Duchess of Soria and Hernani (Unofficial).The Royal arms of Spain differenced by Three-point label azure with the bust of king Alfonso VIII of Castile, elements of the Coat of arms of Soria, and two argent castles, element of the Coat of arms of Hernani.
Cadency of the Spanish Royal House  José Juan Carrión Rangel, Blog de Heráldica.

Label tincture correction (Azure) / Esmalte del lambel corregido (De Azur):Proyecto Galicia : Serie de Heráldica Genealogía y Nobiliaria. T. V (LVIII). La Coruña: Hércules de Ediciones, 2011. ISBN 978-84-92715-31-2. P. 529.
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