The coat of arms of the King of Spain contains the arms from the monarchs of Castille, Leon, Aragon and which other former Iberian kingdom?

The coat of arms of the King of Spain contains the arms from the former Iberian kingdoms of Castile, Leon, Aragon, and Navarre. Navarre was included because it held significant historical and cultural importance within the Iberian Peninsula. It was an independent kingdom for centuries and had been ruled by various monarchs, making its inclusion in the coat of arms a symbol of unity and heritage for the Spanish monarchy.