The title "Duke of Madrid" is a noble title in the Spanish peerage system. It was created in 1561 by King Philip II of Spain for Don Juan de Austria, the illegitimate son of the king. The title has been held by various noble families over the centuries and is associated with the historical significance of Madrid, the capital of Spain. The Duke of Madrid title is part of the broader Spanish aristocracy, which includes various ranks such as counts and marquises. The title reflects the importance of the city of Madrid in Spanish history and governance, symbolizing both power and prestige within the nobility.