Ancient standard of "Guardia Vieja de Castilla" [Old Guard of Castile], BI. 1st King's Immemorial Infantry Regiment of AHQ (Spanish Army)
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<a rel="nofollow" class="external text" href="https://es.slideshare.net/bruscat/1cs6j88s28jvs8godky9">Especial Historia Heráldica:Escudo y bandera de España</a>.  EL FORO DE INTERECONOMÍA, Nº 352 - Lunes, 30 de Abril de 2007