The Nobility of Portugal refers to the social class of aristocrats who held titles and privileges in Portugal throughout its history. This class emerged during the Middle Ages and played a significant role in the country's political, military, and economic affairs. Nobles often owned large estates and were influential in local governance. The Portuguese nobility included various titles such as dukes, marquesses, counts, and barons. Many noble families were connected to the royal family through marriage or service, contributing to the monarchy's stability. The decline of the nobility began in the 19th century with political changes and the establishment of a republic.